xref: /linux/net/mptcp/protocol.h (revision e8dfd42c17faf183415323db1ef0c977be0d6489)
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 #include "mptcp_pm_gen.h"
18 
19 #define MPTCP_SUPPORTED_VERSION	1
20 
21 /* MPTCP option bits */
22 #define OPTION_MPTCP_MPC_SYN	BIT(0)
23 #define OPTION_MPTCP_MPC_SYNACK	BIT(1)
24 #define OPTION_MPTCP_MPC_ACK	BIT(2)
25 #define OPTION_MPTCP_MPJ_SYN	BIT(3)
26 #define OPTION_MPTCP_MPJ_SYNACK	BIT(4)
27 #define OPTION_MPTCP_MPJ_ACK	BIT(5)
28 #define OPTION_MPTCP_ADD_ADDR	BIT(6)
29 #define OPTION_MPTCP_RM_ADDR	BIT(7)
30 #define OPTION_MPTCP_FASTCLOSE	BIT(8)
31 #define OPTION_MPTCP_PRIO	BIT(9)
32 #define OPTION_MPTCP_RST	BIT(10)
33 #define OPTION_MPTCP_DSS	BIT(11)
34 #define OPTION_MPTCP_FAIL	BIT(12)
35 
36 #define OPTION_MPTCP_CSUMREQD	BIT(13)
37 
38 #define OPTIONS_MPTCP_MPC	(OPTION_MPTCP_MPC_SYN | OPTION_MPTCP_MPC_SYNACK | \
39 				 OPTION_MPTCP_MPC_ACK)
40 #define OPTIONS_MPTCP_MPJ	(OPTION_MPTCP_MPJ_SYN | OPTION_MPTCP_MPJ_SYNACK | \
41 				 OPTION_MPTCP_MPJ_ACK)
42 
43 /* MPTCP option subtypes */
44 #define MPTCPOPT_MP_CAPABLE	0
45 #define MPTCPOPT_MP_JOIN	1
46 #define MPTCPOPT_DSS		2
47 #define MPTCPOPT_ADD_ADDR	3
48 #define MPTCPOPT_RM_ADDR	4
49 #define MPTCPOPT_MP_PRIO	5
50 #define MPTCPOPT_MP_FAIL	6
51 #define MPTCPOPT_MP_FASTCLOSE	7
52 #define MPTCPOPT_RST		8
53 
54 /* MPTCP suboption lengths */
55 #define TCPOLEN_MPTCP_MPC_SYN		4
56 #define TCPOLEN_MPTCP_MPC_SYNACK	12
57 #define TCPOLEN_MPTCP_MPC_ACK		20
58 #define TCPOLEN_MPTCP_MPC_ACK_DATA	22
59 #define TCPOLEN_MPTCP_MPJ_SYN		12
60 #define TCPOLEN_MPTCP_MPJ_SYNACK	16
61 #define TCPOLEN_MPTCP_MPJ_ACK		24
62 #define TCPOLEN_MPTCP_DSS_BASE		4
63 #define TCPOLEN_MPTCP_DSS_ACK32		4
64 #define TCPOLEN_MPTCP_DSS_ACK64		8
65 #define TCPOLEN_MPTCP_DSS_MAP32		10
66 #define TCPOLEN_MPTCP_DSS_MAP64		14
67 #define TCPOLEN_MPTCP_DSS_CHECKSUM	2
68 #define TCPOLEN_MPTCP_ADD_ADDR		16
69 #define TCPOLEN_MPTCP_ADD_ADDR_PORT	18
70 #define TCPOLEN_MPTCP_ADD_ADDR_BASE	8
71 #define TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT	10
72 #define TCPOLEN_MPTCP_ADD_ADDR6		28
73 #define TCPOLEN_MPTCP_ADD_ADDR6_PORT	30
74 #define TCPOLEN_MPTCP_ADD_ADDR6_BASE	20
75 #define TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT	22
76 #define TCPOLEN_MPTCP_PORT_LEN		2
77 #define TCPOLEN_MPTCP_PORT_ALIGN	2
78 #define TCPOLEN_MPTCP_RM_ADDR_BASE	3
79 #define TCPOLEN_MPTCP_PRIO		3
80 #define TCPOLEN_MPTCP_PRIO_ALIGN	4
81 #define TCPOLEN_MPTCP_FASTCLOSE		12
82 #define TCPOLEN_MPTCP_RST		4
83 #define TCPOLEN_MPTCP_FAIL		12
84 
85 #define TCPOLEN_MPTCP_MPC_ACK_DATA_CSUM	(TCPOLEN_MPTCP_DSS_CHECKSUM + TCPOLEN_MPTCP_MPC_ACK_DATA)
86 
87 /* MPTCP MP_JOIN flags */
88 #define MPTCPOPT_BACKUP		BIT(0)
89 #define MPTCPOPT_THMAC_LEN	8
90 
91 /* MPTCP MP_CAPABLE flags */
92 #define MPTCP_VERSION_MASK	(0x0F)
93 #define MPTCP_CAP_CHECKSUM_REQD	BIT(7)
94 #define MPTCP_CAP_EXTENSIBILITY	BIT(6)
95 #define MPTCP_CAP_DENY_JOIN_ID0	BIT(5)
96 #define MPTCP_CAP_HMAC_SHA256	BIT(0)
97 #define MPTCP_CAP_FLAG_MASK	(0x1F)
98 
99 /* MPTCP DSS flags */
100 #define MPTCP_DSS_DATA_FIN	BIT(4)
101 #define MPTCP_DSS_DSN64		BIT(3)
102 #define MPTCP_DSS_HAS_MAP	BIT(2)
103 #define MPTCP_DSS_ACK64		BIT(1)
104 #define MPTCP_DSS_HAS_ACK	BIT(0)
105 #define MPTCP_DSS_FLAG_MASK	(0x1F)
106 
107 /* MPTCP ADD_ADDR flags */
108 #define MPTCP_ADDR_ECHO		BIT(0)
109 
110 /* MPTCP MP_PRIO flags */
111 #define MPTCP_PRIO_BKUP		BIT(0)
112 
113 /* MPTCP TCPRST flags */
114 #define MPTCP_RST_TRANSIENT	BIT(0)
115 
116 /* MPTCP socket atomic flags */
117 #define MPTCP_WORK_RTX		1
118 #define MPTCP_FALLBACK_DONE	2
119 #define MPTCP_WORK_CLOSE_SUBFLOW 3
120 
121 /* MPTCP socket release cb flags */
122 #define MPTCP_PUSH_PENDING	1
123 #define MPTCP_CLEAN_UNA		2
124 #define MPTCP_ERROR_REPORT	3
125 #define MPTCP_RETRANSMIT	4
126 #define MPTCP_FLUSH_JOIN_LIST	5
127 #define MPTCP_SYNC_STATE	6
128 #define MPTCP_SYNC_SNDBUF	7
129 
130 struct mptcp_skb_cb {
131 	u64 map_seq;
132 	u64 end_seq;
133 	u32 offset;
134 	u8  has_rxtstamp:1;
135 };
136 
137 #define MPTCP_SKB_CB(__skb)	((struct mptcp_skb_cb *)&((__skb)->cb[0]))
138 
139 static inline bool before64(__u64 seq1, __u64 seq2)
140 {
141 	return (__s64)(seq1 - seq2) < 0;
142 }
143 
144 #define after64(seq2, seq1)	before64(seq1, seq2)
145 
146 struct mptcp_options_received {
147 	u64	sndr_key;
148 	u64	rcvr_key;
149 	u64	data_ack;
150 	u64	data_seq;
151 	u32	subflow_seq;
152 	u16	data_len;
153 	__sum16	csum;
154 	u16	suboptions;
155 	u32	token;
156 	u32	nonce;
157 	u16	use_map:1,
158 		dsn64:1,
159 		data_fin:1,
160 		use_ack:1,
161 		ack64:1,
162 		mpc_map:1,
163 		reset_reason:4,
164 		reset_transient:1,
165 		echo:1,
166 		backup:1,
167 		deny_join_id0:1,
168 		__unused:2;
169 	u8	join_id;
170 	u64	thmac;
171 	u8	hmac[MPTCPOPT_HMAC_LEN];
172 	struct mptcp_addr_info addr;
173 	struct mptcp_rm_list rm_list;
174 	u64	ahmac;
175 	u64	fail_seq;
176 };
177 
178 static inline __be32 mptcp_option(u8 subopt, u8 len, u8 nib, u8 field)
179 {
180 	return htonl((TCPOPT_MPTCP << 24) | (len << 16) | (subopt << 12) |
181 		     ((nib & 0xF) << 8) | field);
182 }
183 
184 enum mptcp_pm_status {
185 	MPTCP_PM_ADD_ADDR_RECEIVED,
186 	MPTCP_PM_ADD_ADDR_SEND_ACK,
187 	MPTCP_PM_RM_ADDR_RECEIVED,
188 	MPTCP_PM_ESTABLISHED,
189 	MPTCP_PM_SUBFLOW_ESTABLISHED,
190 	MPTCP_PM_ALREADY_ESTABLISHED,	/* persistent status, set after ESTABLISHED event */
191 	MPTCP_PM_MPC_ENDPOINT_ACCOUNTED /* persistent status, set after MPC local address is
192 					 * accounted int id_avail_bitmap
193 					 */
194 };
195 
196 enum mptcp_pm_type {
197 	MPTCP_PM_TYPE_KERNEL = 0,
198 	MPTCP_PM_TYPE_USERSPACE,
199 
200 	__MPTCP_PM_TYPE_NR,
201 	__MPTCP_PM_TYPE_MAX = __MPTCP_PM_TYPE_NR - 1,
202 };
203 
204 /* Status bits below MPTCP_PM_ALREADY_ESTABLISHED need pm worker actions */
205 #define MPTCP_PM_WORK_MASK ((1 << MPTCP_PM_ALREADY_ESTABLISHED) - 1)
206 
207 enum mptcp_addr_signal_status {
208 	MPTCP_ADD_ADDR_SIGNAL,
209 	MPTCP_ADD_ADDR_ECHO,
210 	MPTCP_RM_ADDR_SIGNAL,
211 };
212 
213 /* max value of mptcp_addr_info.id */
214 #define MPTCP_PM_MAX_ADDR_ID		U8_MAX
215 
216 struct mptcp_pm_data {
217 	struct mptcp_addr_info local;
218 	struct mptcp_addr_info remote;
219 	struct list_head anno_list;
220 	struct list_head userspace_pm_local_addr_list;
221 
222 	spinlock_t	lock;		/*protects the whole PM data */
223 
224 	u8		addr_signal;
225 	bool		server_side;
226 	bool		work_pending;
227 	bool		accept_addr;
228 	bool		accept_subflow;
229 	bool		remote_deny_join_id0;
230 	u8		add_addr_signaled;
231 	u8		add_addr_accepted;
232 	u8		local_addr_used;
233 	u8		pm_type;
234 	u8		subflows;
235 	u8		status;
236 	DECLARE_BITMAP(id_avail_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);
237 	struct mptcp_rm_list rm_list_tx;
238 	struct mptcp_rm_list rm_list_rx;
239 };
240 
241 struct mptcp_pm_addr_entry {
242 	struct list_head	list;
243 	struct mptcp_addr_info	addr;
244 	u8			flags;
245 	int			ifindex;
246 	struct socket		*lsk;
247 };
248 
249 struct mptcp_data_frag {
250 	struct list_head list;
251 	u64 data_seq;
252 	u16 data_len;
253 	u16 offset;
254 	u16 overhead;
255 	u16 already_sent;
256 	struct page *page;
257 };
258 
259 /* MPTCP connection sock */
260 struct mptcp_sock {
261 	/* inet_connection_sock must be the first member */
262 	struct inet_connection_sock sk;
263 	u64		local_key;		/* protected by the first subflow socket lock
264 						 * lockless access read
265 						 */
266 	u64		remote_key;		/* same as above */
267 	u64		write_seq;
268 	u64		bytes_sent;
269 	u64		snd_nxt;
270 	u64		bytes_received;
271 	u64		ack_seq;
272 	atomic64_t	rcv_wnd_sent;
273 	u64		rcv_data_fin_seq;
274 	u64		bytes_retrans;
275 	u64		bytes_consumed;
276 	int		rmem_fwd_alloc;
277 	int		snd_burst;
278 	int		old_wspace;
279 	u64		recovery_snd_nxt;	/* in recovery mode accept up to this seq;
280 						 * recovery related fields are under data_lock
281 						 * protection
282 						 */
283 	u64		bytes_acked;
284 	u64		snd_una;
285 	u64		wnd_end;
286 	u32		last_data_sent;
287 	u32		last_data_recv;
288 	u32		last_ack_recv;
289 	unsigned long	timer_ival;
290 	u32		token;
291 	int		rmem_released;
292 	unsigned long	flags;
293 	unsigned long	cb_flags;
294 	bool		recovery;		/* closing subflow write queue reinjected */
295 	bool		can_ack;
296 	bool		fully_established;
297 	bool		rcv_data_fin;
298 	bool		snd_data_fin_enable;
299 	bool		rcv_fastclose;
300 	bool		use_64bit_ack; /* Set when we received a 64-bit DSN */
301 	bool		csum_enabled;
302 	bool		allow_infinite_fallback;
303 	u8		pending_state; /* A subflow asked to set this sk_state,
304 					* protected by the msk data lock
305 					*/
306 	u8		mpc_endpoint_id;
307 	u8		recvmsg_inq:1,
308 			cork:1,
309 			nodelay:1,
310 			fastopening:1,
311 			in_accept_queue:1,
312 			free_first:1,
313 			rcvspace_init:1;
314 	u32		notsent_lowat;
315 	struct work_struct work;
316 	struct sk_buff  *ooo_last_skb;
317 	struct rb_root  out_of_order_queue;
318 	struct sk_buff_head receive_queue;
319 	struct list_head conn_list;
320 	struct list_head rtx_queue;
321 	struct mptcp_data_frag *first_pending;
322 	struct list_head join_list;
323 	struct sock	*first; /* The mptcp ops can safely dereference, using suitable
324 				 * ONCE annotation, the subflow outside the socket
325 				 * lock as such sock is freed after close().
326 				 */
327 	struct mptcp_pm_data	pm;
328 	struct mptcp_sched_ops	*sched;
329 	struct {
330 		u32	space;	/* bytes copied in last measurement window */
331 		u32	copied; /* bytes copied in this measurement window */
332 		u64	time;	/* start time of measurement window */
333 		u64	rtt_us; /* last maximum rtt of subflows */
334 	} rcvq_space;
335 	u8		scaling_ratio;
336 
337 	u32		subflow_id;
338 	u32		setsockopt_seq;
339 	char		ca_name[TCP_CA_NAME_MAX];
340 };
341 
342 #define mptcp_data_lock(sk) spin_lock_bh(&(sk)->sk_lock.slock)
343 #define mptcp_data_unlock(sk) spin_unlock_bh(&(sk)->sk_lock.slock)
344 
345 #define mptcp_for_each_subflow(__msk, __subflow)			\
346 	list_for_each_entry(__subflow, &((__msk)->conn_list), node)
347 #define mptcp_for_each_subflow_safe(__msk, __subflow, __tmp)			\
348 	list_for_each_entry_safe(__subflow, __tmp, &((__msk)->conn_list), node)
349 
350 extern struct genl_family mptcp_genl_family;
351 
352 static inline void msk_owned_by_me(const struct mptcp_sock *msk)
353 {
354 	sock_owned_by_me((const struct sock *)msk);
355 }
356 
357 #ifdef CONFIG_DEBUG_NET
358 /* MPTCP-specific: we might (indirectly) call this helper with the wrong sk */
359 #undef tcp_sk
360 #define tcp_sk(ptr) ({								\
361 	typeof(ptr) _ptr = (ptr);						\
362 	WARN_ON(_ptr->sk_protocol != IPPROTO_TCP);				\
363 	container_of_const(_ptr, struct tcp_sock, inet_conn.icsk_inet.sk);	\
364 })
365 #define mptcp_sk(ptr) ({						\
366 	typeof(ptr) _ptr = (ptr);					\
367 	WARN_ON(_ptr->sk_protocol != IPPROTO_MPTCP);			\
368 	container_of_const(_ptr, struct mptcp_sock, sk.icsk_inet.sk);	\
369 })
370 
371 #else /* !CONFIG_DEBUG_NET */
372 #define mptcp_sk(ptr) container_of_const(ptr, struct mptcp_sock, sk.icsk_inet.sk)
373 #endif
374 
375 /* the msk socket don't use the backlog, also account for the bulk
376  * free memory
377  */
378 static inline int __mptcp_rmem(const struct sock *sk)
379 {
380 	return atomic_read(&sk->sk_rmem_alloc) - READ_ONCE(mptcp_sk(sk)->rmem_released);
381 }
382 
383 static inline int mptcp_win_from_space(const struct sock *sk, int space)
384 {
385 	return __tcp_win_from_space(mptcp_sk(sk)->scaling_ratio, space);
386 }
387 
388 static inline int __mptcp_space(const struct sock *sk)
389 {
390 	return mptcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf) - __mptcp_rmem(sk));
391 }
392 
393 static inline struct mptcp_data_frag *mptcp_send_head(const struct sock *sk)
394 {
395 	const struct mptcp_sock *msk = mptcp_sk(sk);
396 
397 	return READ_ONCE(msk->first_pending);
398 }
399 
400 static inline struct mptcp_data_frag *mptcp_send_next(struct sock *sk)
401 {
402 	struct mptcp_sock *msk = mptcp_sk(sk);
403 	struct mptcp_data_frag *cur;
404 
405 	cur = msk->first_pending;
406 	return list_is_last(&cur->list, &msk->rtx_queue) ? NULL :
407 						     list_next_entry(cur, list);
408 }
409 
410 static inline struct mptcp_data_frag *mptcp_pending_tail(const struct sock *sk)
411 {
412 	const struct mptcp_sock *msk = mptcp_sk(sk);
413 
414 	if (!msk->first_pending)
415 		return NULL;
416 
417 	if (WARN_ON_ONCE(list_empty(&msk->rtx_queue)))
418 		return NULL;
419 
420 	return list_last_entry(&msk->rtx_queue, struct mptcp_data_frag, list);
421 }
422 
423 static inline struct mptcp_data_frag *mptcp_rtx_head(struct sock *sk)
424 {
425 	struct mptcp_sock *msk = mptcp_sk(sk);
426 
427 	if (msk->snd_una == msk->snd_nxt)
428 		return NULL;
429 
430 	return list_first_entry_or_null(&msk->rtx_queue, struct mptcp_data_frag, list);
431 }
432 
433 struct csum_pseudo_header {
434 	__be64 data_seq;
435 	__be32 subflow_seq;
436 	__be16 data_len;
437 	__sum16 csum;
438 };
439 
440 struct mptcp_subflow_request_sock {
441 	struct	tcp_request_sock sk;
442 	u16	mp_capable : 1,
443 		mp_join : 1,
444 		backup : 1,
445 		csum_reqd : 1,
446 		allow_join_id0 : 1;
447 	u8	local_id;
448 	u8	remote_id;
449 	u64	local_key;
450 	u64	idsn;
451 	u32	token;
452 	u32	ssn_offset;
453 	u64	thmac;
454 	u32	local_nonce;
455 	u32	remote_nonce;
456 	struct mptcp_sock	*msk;
457 	struct hlist_nulls_node token_node;
458 };
459 
460 static inline struct mptcp_subflow_request_sock *
461 mptcp_subflow_rsk(const struct request_sock *rsk)
462 {
463 	return (struct mptcp_subflow_request_sock *)rsk;
464 }
465 
466 struct mptcp_delegated_action {
467 	struct napi_struct napi;
468 	struct list_head head;
469 };
470 
471 DECLARE_PER_CPU(struct mptcp_delegated_action, mptcp_delegated_actions);
472 
473 #define MPTCP_DELEGATE_SCHEDULED	0
474 #define MPTCP_DELEGATE_SEND		1
475 #define MPTCP_DELEGATE_ACK		2
476 #define MPTCP_DELEGATE_SNDBUF		3
477 
478 #define MPTCP_DELEGATE_ACTIONS_MASK	(~BIT(MPTCP_DELEGATE_SCHEDULED))
479 /* MPTCP subflow context */
480 struct mptcp_subflow_context {
481 	struct	list_head node;/* conn_list of subflows */
482 
483 	struct_group(reset,
484 
485 	unsigned long avg_pacing_rate; /* protected by msk socket lock */
486 	u64	local_key;
487 	u64	remote_key;
488 	u64	idsn;
489 	u64	map_seq;
490 	u32	snd_isn;
491 	u32	token;
492 	u32	rel_write_seq;
493 	u32	map_subflow_seq;
494 	u32	ssn_offset;
495 	u32	map_data_len;
496 	__wsum	map_data_csum;
497 	u32	map_csum_len;
498 	u32	request_mptcp : 1,  /* send MP_CAPABLE */
499 		request_join : 1,   /* send MP_JOIN */
500 		request_bkup : 1,
501 		mp_capable : 1,	    /* remote is MPTCP capable */
502 		mp_join : 1,	    /* remote is JOINing */
503 		fully_established : 1,	    /* path validated */
504 		pm_notified : 1,    /* PM hook called for established status */
505 		conn_finished : 1,
506 		map_valid : 1,
507 		map_csum_reqd : 1,
508 		map_data_fin : 1,
509 		mpc_map : 1,
510 		backup : 1,
511 		send_mp_prio : 1,
512 		send_mp_fail : 1,
513 		send_fastclose : 1,
514 		send_infinite_map : 1,
515 		remote_key_valid : 1,        /* received the peer key from */
516 		disposable : 1,	    /* ctx can be free at ulp release time */
517 		stale : 1,	    /* unable to snd/rcv data, do not use for xmit */
518 		valid_csum_seen : 1,        /* at least one csum validated */
519 		is_mptfo : 1,	    /* subflow is doing TFO */
520 		__unused : 10;
521 	bool	data_avail;
522 	bool	scheduled;
523 	u32	remote_nonce;
524 	u64	thmac;
525 	u32	local_nonce;
526 	u32	remote_token;
527 	union {
528 		u8	hmac[MPTCPOPT_HMAC_LEN]; /* MPJ subflow only */
529 		u64	iasn;	    /* initial ack sequence number, MPC subflows only */
530 	};
531 	s16	local_id;	    /* if negative not initialized yet */
532 	u8	remote_id;
533 	u8	reset_seen:1;
534 	u8	reset_transient:1;
535 	u8	reset_reason:4;
536 	u8	stale_count;
537 
538 	u32	subflow_id;
539 
540 	long	delegated_status;
541 	unsigned long	fail_tout;
542 
543 	);
544 
545 	struct	list_head delegated_node;   /* link into delegated_action, protected by local BH */
546 
547 	u32	setsockopt_seq;
548 	u32	stale_rcv_tstamp;
549 	int     cached_sndbuf;	    /* sndbuf size when last synced with the msk sndbuf,
550 				     * protected by the msk socket lock
551 				     */
552 
553 	struct	sock *tcp_sock;	    /* tcp sk backpointer */
554 	struct	sock *conn;	    /* parent mptcp_sock */
555 	const	struct inet_connection_sock_af_ops *icsk_af_ops;
556 	void	(*tcp_state_change)(struct sock *sk);
557 	void	(*tcp_error_report)(struct sock *sk);
558 
559 	struct	rcu_head rcu;
560 };
561 
562 static inline struct mptcp_subflow_context *
563 mptcp_subflow_ctx(const struct sock *sk)
564 {
565 	const struct inet_connection_sock *icsk = inet_csk(sk);
566 
567 	/* Use RCU on icsk_ulp_data only for sock diag code */
568 	return (__force struct mptcp_subflow_context *)icsk->icsk_ulp_data;
569 }
570 
571 static inline struct sock *
572 mptcp_subflow_tcp_sock(const struct mptcp_subflow_context *subflow)
573 {
574 	return subflow->tcp_sock;
575 }
576 
577 static inline void
578 mptcp_subflow_ctx_reset(struct mptcp_subflow_context *subflow)
579 {
580 	memset(&subflow->reset, 0, sizeof(subflow->reset));
581 	subflow->request_mptcp = 1;
582 	WRITE_ONCE(subflow->local_id, -1);
583 }
584 
585 /* Convert reset reasons in MPTCP to enum sk_rst_reason type */
586 static inline enum sk_rst_reason
587 sk_rst_convert_mptcp_reason(u32 reason)
588 {
589 	switch (reason) {
590 	case MPTCP_RST_EUNSPEC:
591 		return SK_RST_REASON_MPTCP_RST_EUNSPEC;
592 	case MPTCP_RST_EMPTCP:
593 		return SK_RST_REASON_MPTCP_RST_EMPTCP;
594 	case MPTCP_RST_ERESOURCE:
595 		return SK_RST_REASON_MPTCP_RST_ERESOURCE;
596 	case MPTCP_RST_EPROHIBIT:
597 		return SK_RST_REASON_MPTCP_RST_EPROHIBIT;
598 	case MPTCP_RST_EWQ2BIG:
599 		return SK_RST_REASON_MPTCP_RST_EWQ2BIG;
600 	case MPTCP_RST_EBADPERF:
601 		return SK_RST_REASON_MPTCP_RST_EBADPERF;
602 	case MPTCP_RST_EMIDDLEBOX:
603 		return SK_RST_REASON_MPTCP_RST_EMIDDLEBOX;
604 	default:
605 		/* It should not happen, or else errors may occur
606 		 * in MPTCP layer
607 		 */
608 		return SK_RST_REASON_ERROR;
609 	}
610 }
611 
612 static inline void
613 mptcp_send_active_reset_reason(struct sock *sk)
614 {
615 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
616 	enum sk_rst_reason reason;
617 
618 	reason = sk_rst_convert_mptcp_reason(subflow->reset_reason);
619 	tcp_send_active_reset(sk, GFP_ATOMIC, reason);
620 }
621 
622 static inline u64
623 mptcp_subflow_get_map_offset(const struct mptcp_subflow_context *subflow)
624 {
625 	return tcp_sk(mptcp_subflow_tcp_sock(subflow))->copied_seq -
626 		      subflow->ssn_offset -
627 		      subflow->map_subflow_seq;
628 }
629 
630 static inline u64
631 mptcp_subflow_get_mapped_dsn(const struct mptcp_subflow_context *subflow)
632 {
633 	return subflow->map_seq + mptcp_subflow_get_map_offset(subflow);
634 }
635 
636 void mptcp_subflow_process_delegated(struct sock *ssk, long actions);
637 
638 static inline void mptcp_subflow_delegate(struct mptcp_subflow_context *subflow, int action)
639 {
640 	long old, set_bits = BIT(MPTCP_DELEGATE_SCHEDULED) | BIT(action);
641 	struct mptcp_delegated_action *delegated;
642 	bool schedule;
643 
644 	/* the caller held the subflow bh socket lock */
645 	lockdep_assert_in_softirq();
646 
647 	/* The implied barrier pairs with tcp_release_cb_override()
648 	 * mptcp_napi_poll(), and ensures the below list check sees list
649 	 * updates done prior to delegated status bits changes
650 	 */
651 	old = set_mask_bits(&subflow->delegated_status, 0, set_bits);
652 	if (!(old & BIT(MPTCP_DELEGATE_SCHEDULED))) {
653 		if (WARN_ON_ONCE(!list_empty(&subflow->delegated_node)))
654 			return;
655 
656 		delegated = this_cpu_ptr(&mptcp_delegated_actions);
657 		schedule = list_empty(&delegated->head);
658 		list_add_tail(&subflow->delegated_node, &delegated->head);
659 		sock_hold(mptcp_subflow_tcp_sock(subflow));
660 		if (schedule)
661 			napi_schedule(&delegated->napi);
662 	}
663 }
664 
665 static inline struct mptcp_subflow_context *
666 mptcp_subflow_delegated_next(struct mptcp_delegated_action *delegated)
667 {
668 	struct mptcp_subflow_context *ret;
669 
670 	if (list_empty(&delegated->head))
671 		return NULL;
672 
673 	ret = list_first_entry(&delegated->head, struct mptcp_subflow_context, delegated_node);
674 	list_del_init(&ret->delegated_node);
675 	return ret;
676 }
677 
678 int mptcp_is_enabled(const struct net *net);
679 unsigned int mptcp_get_add_addr_timeout(const struct net *net);
680 int mptcp_is_checksum_enabled(const struct net *net);
681 int mptcp_allow_join_id0(const struct net *net);
682 unsigned int mptcp_stale_loss_cnt(const struct net *net);
683 unsigned int mptcp_close_timeout(const struct sock *sk);
684 int mptcp_get_pm_type(const struct net *net);
685 const char *mptcp_get_scheduler(const struct net *net);
686 void __mptcp_subflow_fully_established(struct mptcp_sock *msk,
687 				       struct mptcp_subflow_context *subflow,
688 				       const struct mptcp_options_received *mp_opt);
689 bool __mptcp_retransmit_pending_data(struct sock *sk);
690 void mptcp_check_and_set_pending(struct sock *sk);
691 void __mptcp_push_pending(struct sock *sk, unsigned int flags);
692 bool mptcp_subflow_data_available(struct sock *sk);
693 void __init mptcp_subflow_init(void);
694 void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how);
695 void mptcp_close_ssk(struct sock *sk, struct sock *ssk,
696 		     struct mptcp_subflow_context *subflow);
697 void __mptcp_subflow_send_ack(struct sock *ssk);
698 void mptcp_subflow_reset(struct sock *ssk);
699 void mptcp_subflow_queue_clean(struct sock *sk, struct sock *ssk);
700 void mptcp_sock_graft(struct sock *sk, struct socket *parent);
701 struct sock *__mptcp_nmpc_sk(struct mptcp_sock *msk);
702 bool __mptcp_close(struct sock *sk, long timeout);
703 void mptcp_cancel_work(struct sock *sk);
704 void __mptcp_unaccepted_force_close(struct sock *sk);
705 void mptcp_set_owner_r(struct sk_buff *skb, struct sock *sk);
706 void mptcp_set_state(struct sock *sk, int state);
707 
708 bool mptcp_addresses_equal(const struct mptcp_addr_info *a,
709 			   const struct mptcp_addr_info *b, bool use_port);
710 void mptcp_local_address(const struct sock_common *skc, struct mptcp_addr_info *addr);
711 
712 /* called with sk socket lock held */
713 int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
714 			    const struct mptcp_addr_info *remote);
715 int mptcp_subflow_create_socket(struct sock *sk, unsigned short family,
716 				struct socket **new_sock);
717 void mptcp_info2sockaddr(const struct mptcp_addr_info *info,
718 			 struct sockaddr_storage *addr,
719 			 unsigned short family);
720 struct mptcp_sched_ops *mptcp_sched_find(const char *name);
721 int mptcp_register_scheduler(struct mptcp_sched_ops *sched);
722 void mptcp_unregister_scheduler(struct mptcp_sched_ops *sched);
723 void mptcp_sched_init(void);
724 int mptcp_init_sched(struct mptcp_sock *msk,
725 		     struct mptcp_sched_ops *sched);
726 void mptcp_release_sched(struct mptcp_sock *msk);
727 void mptcp_subflow_set_scheduled(struct mptcp_subflow_context *subflow,
728 				 bool scheduled);
729 struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk);
730 struct sock *mptcp_subflow_get_retrans(struct mptcp_sock *msk);
731 int mptcp_sched_get_send(struct mptcp_sock *msk);
732 int mptcp_sched_get_retrans(struct mptcp_sock *msk);
733 
734 static inline u64 mptcp_data_avail(const struct mptcp_sock *msk)
735 {
736 	return READ_ONCE(msk->bytes_received) - READ_ONCE(msk->bytes_consumed);
737 }
738 
739 static inline bool mptcp_epollin_ready(const struct sock *sk)
740 {
741 	/* mptcp doesn't have to deal with small skbs in the receive queue,
742 	 * at it can always coalesce them
743 	 */
744 	return (mptcp_data_avail(mptcp_sk(sk)) >= sk->sk_rcvlowat) ||
745 	       (mem_cgroup_sockets_enabled && sk->sk_memcg &&
746 		mem_cgroup_under_socket_pressure(sk->sk_memcg)) ||
747 	       READ_ONCE(tcp_memory_pressure);
748 }
749 
750 int mptcp_set_rcvlowat(struct sock *sk, int val);
751 
752 static inline bool __tcp_can_send(const struct sock *ssk)
753 {
754 	/* only send if our side has not closed yet */
755 	return ((1 << inet_sk_state_load(ssk)) & (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT));
756 }
757 
758 static inline bool __mptcp_subflow_active(struct mptcp_subflow_context *subflow)
759 {
760 	/* can't send if JOIN hasn't completed yet (i.e. is usable for mptcp) */
761 	if (subflow->request_join && !subflow->fully_established)
762 		return false;
763 
764 	return __tcp_can_send(mptcp_subflow_tcp_sock(subflow));
765 }
766 
767 void mptcp_subflow_set_active(struct mptcp_subflow_context *subflow);
768 
769 bool mptcp_subflow_active(struct mptcp_subflow_context *subflow);
770 
771 void mptcp_subflow_drop_ctx(struct sock *ssk);
772 
773 static inline void mptcp_subflow_tcp_fallback(struct sock *sk,
774 					      struct mptcp_subflow_context *ctx)
775 {
776 	sk->sk_data_ready = sock_def_readable;
777 	sk->sk_state_change = ctx->tcp_state_change;
778 	sk->sk_write_space = sk_stream_write_space;
779 	sk->sk_error_report = ctx->tcp_error_report;
780 
781 	inet_csk(sk)->icsk_af_ops = ctx->icsk_af_ops;
782 }
783 
784 void __init mptcp_proto_init(void);
785 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
786 int __init mptcp_proto_v6_init(void);
787 #endif
788 
789 struct sock *mptcp_sk_clone_init(const struct sock *sk,
790 				 const struct mptcp_options_received *mp_opt,
791 				 struct sock *ssk,
792 				 struct request_sock *req);
793 void mptcp_get_options(const struct sk_buff *skb,
794 		       struct mptcp_options_received *mp_opt);
795 
796 void mptcp_finish_connect(struct sock *sk);
797 void __mptcp_sync_state(struct sock *sk, int state);
798 void mptcp_reset_tout_timer(struct mptcp_sock *msk, unsigned long fail_tout);
799 
800 static inline void mptcp_stop_tout_timer(struct sock *sk)
801 {
802 	if (!inet_csk(sk)->icsk_mtup.probe_timestamp)
803 		return;
804 
805 	sk_stop_timer(sk, &sk->sk_timer);
806 	inet_csk(sk)->icsk_mtup.probe_timestamp = 0;
807 }
808 
809 static inline void mptcp_set_close_tout(struct sock *sk, unsigned long tout)
810 {
811 	/* avoid 0 timestamp, as that means no close timeout */
812 	inet_csk(sk)->icsk_mtup.probe_timestamp = tout ? : 1;
813 }
814 
815 static inline void mptcp_start_tout_timer(struct sock *sk)
816 {
817 	mptcp_set_close_tout(sk, tcp_jiffies32);
818 	mptcp_reset_tout_timer(mptcp_sk(sk), 0);
819 }
820 
821 static inline bool mptcp_is_fully_established(struct sock *sk)
822 {
823 	return inet_sk_state_load(sk) == TCP_ESTABLISHED &&
824 	       READ_ONCE(mptcp_sk(sk)->fully_established);
825 }
826 
827 void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk);
828 void mptcp_data_ready(struct sock *sk, struct sock *ssk);
829 bool mptcp_finish_join(struct sock *sk);
830 bool mptcp_schedule_work(struct sock *sk);
831 int mptcp_setsockopt(struct sock *sk, int level, int optname,
832 		     sockptr_t optval, unsigned int optlen);
833 int mptcp_getsockopt(struct sock *sk, int level, int optname,
834 		     char __user *optval, int __user *option);
835 
836 u64 __mptcp_expand_seq(u64 old_seq, u64 cur_seq);
837 static inline u64 mptcp_expand_seq(u64 old_seq, u64 cur_seq, bool use_64bit)
838 {
839 	if (use_64bit)
840 		return cur_seq;
841 
842 	return __mptcp_expand_seq(old_seq, cur_seq);
843 }
844 void __mptcp_check_push(struct sock *sk, struct sock *ssk);
845 void __mptcp_data_acked(struct sock *sk);
846 void __mptcp_error_report(struct sock *sk);
847 bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit);
848 static inline bool mptcp_data_fin_enabled(const struct mptcp_sock *msk)
849 {
850 	return READ_ONCE(msk->snd_data_fin_enable) &&
851 	       READ_ONCE(msk->write_seq) == READ_ONCE(msk->snd_nxt);
852 }
853 
854 static inline u32 mptcp_notsent_lowat(const struct sock *sk)
855 {
856 	struct net *net = sock_net(sk);
857 	u32 val;
858 
859 	val = READ_ONCE(mptcp_sk(sk)->notsent_lowat);
860 	return val ?: READ_ONCE(net->ipv4.sysctl_tcp_notsent_lowat);
861 }
862 
863 static inline bool mptcp_stream_memory_free(const struct sock *sk, int wake)
864 {
865 	const struct mptcp_sock *msk = mptcp_sk(sk);
866 	u32 notsent_bytes;
867 
868 	notsent_bytes = READ_ONCE(msk->write_seq) - READ_ONCE(msk->snd_nxt);
869 	return (notsent_bytes << wake) < mptcp_notsent_lowat(sk);
870 }
871 
872 static inline bool __mptcp_stream_is_writeable(const struct sock *sk, int wake)
873 {
874 	return mptcp_stream_memory_free(sk, wake) &&
875 	       __sk_stream_is_writeable(sk, wake);
876 }
877 
878 static inline void mptcp_write_space(struct sock *sk)
879 {
880 	/* pairs with memory barrier in mptcp_poll */
881 	smp_mb();
882 	if (mptcp_stream_memory_free(sk, 1))
883 		sk_stream_write_space(sk);
884 }
885 
886 static inline void __mptcp_sync_sndbuf(struct sock *sk)
887 {
888 	struct mptcp_subflow_context *subflow;
889 	int ssk_sndbuf, new_sndbuf;
890 
891 	if (sk->sk_userlocks & SOCK_SNDBUF_LOCK)
892 		return;
893 
894 	new_sndbuf = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_wmem[0]);
895 	mptcp_for_each_subflow(mptcp_sk(sk), subflow) {
896 		ssk_sndbuf =  READ_ONCE(mptcp_subflow_tcp_sock(subflow)->sk_sndbuf);
897 
898 		subflow->cached_sndbuf = ssk_sndbuf;
899 		new_sndbuf += ssk_sndbuf;
900 	}
901 
902 	/* the msk max wmem limit is <nr_subflows> * tcp wmem[2] */
903 	WRITE_ONCE(sk->sk_sndbuf, new_sndbuf);
904 	mptcp_write_space(sk);
905 }
906 
907 /* The called held both the msk socket and the subflow socket locks,
908  * possibly under BH
909  */
910 static inline void __mptcp_propagate_sndbuf(struct sock *sk, struct sock *ssk)
911 {
912 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
913 
914 	if (READ_ONCE(ssk->sk_sndbuf) != subflow->cached_sndbuf)
915 		__mptcp_sync_sndbuf(sk);
916 }
917 
918 /* the caller held only the subflow socket lock, either in process or
919  * BH context. Additionally this can be called under the msk data lock,
920  * so we can't acquire such lock here: let the delegate action acquires
921  * the needed locks in suitable order.
922  */
923 static inline void mptcp_propagate_sndbuf(struct sock *sk, struct sock *ssk)
924 {
925 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
926 
927 	if (likely(READ_ONCE(ssk->sk_sndbuf) == subflow->cached_sndbuf))
928 		return;
929 
930 	local_bh_disable();
931 	mptcp_subflow_delegate(subflow, MPTCP_DELEGATE_SNDBUF);
932 	local_bh_enable();
933 }
934 
935 void mptcp_destroy_common(struct mptcp_sock *msk, unsigned int flags);
936 
937 #define MPTCP_TOKEN_MAX_RETRIES	4
938 
939 void __init mptcp_token_init(void);
940 static inline void mptcp_token_init_request(struct request_sock *req)
941 {
942 	mptcp_subflow_rsk(req)->token_node.pprev = NULL;
943 }
944 
945 int mptcp_token_new_request(struct request_sock *req);
946 void mptcp_token_destroy_request(struct request_sock *req);
947 int mptcp_token_new_connect(struct sock *ssk);
948 void mptcp_token_accept(struct mptcp_subflow_request_sock *r,
949 			struct mptcp_sock *msk);
950 bool mptcp_token_exists(u32 token);
951 struct mptcp_sock *mptcp_token_get_sock(struct net *net, u32 token);
952 struct mptcp_sock *mptcp_token_iter_next(const struct net *net, long *s_slot,
953 					 long *s_num);
954 void mptcp_token_destroy(struct mptcp_sock *msk);
955 
956 void mptcp_crypto_key_sha(u64 key, u32 *token, u64 *idsn);
957 
958 void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u8 *msg, int len, void *hmac);
959 __sum16 __mptcp_make_csum(u64 data_seq, u32 subflow_seq, u16 data_len, __wsum sum);
960 
961 void __init mptcp_pm_init(void);
962 void mptcp_pm_data_init(struct mptcp_sock *msk);
963 void mptcp_pm_data_reset(struct mptcp_sock *msk);
964 int mptcp_pm_parse_addr(struct nlattr *attr, struct genl_info *info,
965 			struct mptcp_addr_info *addr);
966 int mptcp_pm_parse_entry(struct nlattr *attr, struct genl_info *info,
967 			 bool require_family,
968 			 struct mptcp_pm_addr_entry *entry);
969 bool mptcp_pm_addr_families_match(const struct sock *sk,
970 				  const struct mptcp_addr_info *loc,
971 				  const struct mptcp_addr_info *rem);
972 void mptcp_pm_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk);
973 void mptcp_pm_nl_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk);
974 void mptcp_pm_new_connection(struct mptcp_sock *msk, const struct sock *ssk, int server_side);
975 void mptcp_pm_fully_established(struct mptcp_sock *msk, const struct sock *ssk);
976 bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk);
977 void mptcp_pm_connection_closed(struct mptcp_sock *msk);
978 void mptcp_pm_subflow_established(struct mptcp_sock *msk);
979 bool mptcp_pm_nl_check_work_pending(struct mptcp_sock *msk);
980 void mptcp_pm_subflow_check_next(struct mptcp_sock *msk,
981 				 const struct mptcp_subflow_context *subflow);
982 void mptcp_pm_add_addr_received(const struct sock *ssk,
983 				const struct mptcp_addr_info *addr);
984 void mptcp_pm_add_addr_echoed(struct mptcp_sock *msk,
985 			      const struct mptcp_addr_info *addr);
986 void mptcp_pm_add_addr_send_ack(struct mptcp_sock *msk);
987 void mptcp_pm_nl_addr_send_ack(struct mptcp_sock *msk);
988 void mptcp_pm_rm_addr_received(struct mptcp_sock *msk,
989 			       const struct mptcp_rm_list *rm_list);
990 void mptcp_pm_mp_prio_received(struct sock *sk, u8 bkup);
991 void mptcp_pm_mp_fail_received(struct sock *sk, u64 fail_seq);
992 int mptcp_pm_nl_mp_prio_send_ack(struct mptcp_sock *msk,
993 				 struct mptcp_addr_info *addr,
994 				 struct mptcp_addr_info *rem,
995 				 u8 bkup);
996 bool mptcp_pm_alloc_anno_list(struct mptcp_sock *msk,
997 			      const struct mptcp_addr_info *addr);
998 void mptcp_pm_free_anno_list(struct mptcp_sock *msk);
999 bool mptcp_pm_sport_in_anno_list(struct mptcp_sock *msk, const struct sock *sk);
1000 struct mptcp_pm_add_entry *
1001 mptcp_pm_del_add_timer(struct mptcp_sock *msk,
1002 		       const struct mptcp_addr_info *addr, bool check_id);
1003 struct mptcp_pm_add_entry *
1004 mptcp_lookup_anno_list_by_saddr(const struct mptcp_sock *msk,
1005 				const struct mptcp_addr_info *addr);
1006 int mptcp_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk,
1007 					 unsigned int id,
1008 					 u8 *flags, int *ifindex);
1009 int mptcp_pm_nl_get_flags_and_ifindex_by_id(struct mptcp_sock *msk, unsigned int id,
1010 					    u8 *flags, int *ifindex);
1011 int mptcp_userspace_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk,
1012 						   unsigned int id,
1013 						   u8 *flags, int *ifindex);
1014 int mptcp_pm_set_flags(struct sk_buff *skb, struct genl_info *info);
1015 int mptcp_pm_nl_set_flags(struct sk_buff *skb, struct genl_info *info);
1016 int mptcp_userspace_pm_set_flags(struct sk_buff *skb, struct genl_info *info);
1017 int mptcp_pm_announce_addr(struct mptcp_sock *msk,
1018 			   const struct mptcp_addr_info *addr,
1019 			   bool echo);
1020 int mptcp_pm_remove_addr(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list);
1021 int mptcp_pm_remove_subflow(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list);
1022 void mptcp_pm_remove_addrs(struct mptcp_sock *msk, struct list_head *rm_list);
1023 
1024 void mptcp_free_local_addr_list(struct mptcp_sock *msk);
1025 
1026 void mptcp_event(enum mptcp_event_type type, const struct mptcp_sock *msk,
1027 		 const struct sock *ssk, gfp_t gfp);
1028 void mptcp_event_addr_announced(const struct sock *ssk, const struct mptcp_addr_info *info);
1029 void mptcp_event_addr_removed(const struct mptcp_sock *msk, u8 id);
1030 void mptcp_event_pm_listener(const struct sock *ssk,
1031 			     enum mptcp_event_type event);
1032 bool mptcp_userspace_pm_active(const struct mptcp_sock *msk);
1033 
1034 void __mptcp_fastopen_gen_msk_ackseq(struct mptcp_sock *msk, struct mptcp_subflow_context *subflow,
1035 				     const struct mptcp_options_received *mp_opt);
1036 void mptcp_fastopen_subflow_synack_set_params(struct mptcp_subflow_context *subflow,
1037 					      struct request_sock *req);
1038 int mptcp_nl_fill_addr(struct sk_buff *skb,
1039 		       struct mptcp_pm_addr_entry *entry);
1040 
1041 static inline bool mptcp_pm_should_add_signal(struct mptcp_sock *msk)
1042 {
1043 	return READ_ONCE(msk->pm.addr_signal) &
1044 		(BIT(MPTCP_ADD_ADDR_SIGNAL) | BIT(MPTCP_ADD_ADDR_ECHO));
1045 }
1046 
1047 static inline bool mptcp_pm_should_add_signal_addr(struct mptcp_sock *msk)
1048 {
1049 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_SIGNAL);
1050 }
1051 
1052 static inline bool mptcp_pm_should_add_signal_echo(struct mptcp_sock *msk)
1053 {
1054 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_ADD_ADDR_ECHO);
1055 }
1056 
1057 static inline bool mptcp_pm_should_rm_signal(struct mptcp_sock *msk)
1058 {
1059 	return READ_ONCE(msk->pm.addr_signal) & BIT(MPTCP_RM_ADDR_SIGNAL);
1060 }
1061 
1062 static inline bool mptcp_pm_is_userspace(const struct mptcp_sock *msk)
1063 {
1064 	return READ_ONCE(msk->pm.pm_type) == MPTCP_PM_TYPE_USERSPACE;
1065 }
1066 
1067 static inline bool mptcp_pm_is_kernel(const struct mptcp_sock *msk)
1068 {
1069 	return READ_ONCE(msk->pm.pm_type) == MPTCP_PM_TYPE_KERNEL;
1070 }
1071 
1072 static inline unsigned int mptcp_add_addr_len(int family, bool echo, bool port)
1073 {
1074 	u8 len = TCPOLEN_MPTCP_ADD_ADDR_BASE;
1075 
1076 	if (family == AF_INET6)
1077 		len = TCPOLEN_MPTCP_ADD_ADDR6_BASE;
1078 	if (!echo)
1079 		len += MPTCPOPT_THMAC_LEN;
1080 	/* account for 2 trailing 'nop' options */
1081 	if (port)
1082 		len += TCPOLEN_MPTCP_PORT_LEN + TCPOLEN_MPTCP_PORT_ALIGN;
1083 
1084 	return len;
1085 }
1086 
1087 static inline int mptcp_rm_addr_len(const struct mptcp_rm_list *rm_list)
1088 {
1089 	if (rm_list->nr == 0 || rm_list->nr > MPTCP_RM_IDS_MAX)
1090 		return -EINVAL;
1091 
1092 	return TCPOLEN_MPTCP_RM_ADDR_BASE + roundup(rm_list->nr - 1, 4) + 1;
1093 }
1094 
1095 bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, const struct sk_buff *skb,
1096 			      unsigned int opt_size, unsigned int remaining,
1097 			      struct mptcp_addr_info *addr, bool *echo,
1098 			      bool *drop_other_suboptions);
1099 bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
1100 			     struct mptcp_rm_list *rm_list);
1101 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
1102 int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
1103 int mptcp_userspace_pm_get_local_id(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
1104 int mptcp_pm_dump_addr(struct sk_buff *msg, struct netlink_callback *cb);
1105 int mptcp_pm_nl_dump_addr(struct sk_buff *msg,
1106 			  struct netlink_callback *cb);
1107 int mptcp_userspace_pm_dump_addr(struct sk_buff *msg,
1108 				 struct netlink_callback *cb);
1109 int mptcp_pm_get_addr(struct sk_buff *skb, struct genl_info *info);
1110 int mptcp_pm_nl_get_addr(struct sk_buff *skb, struct genl_info *info);
1111 int mptcp_userspace_pm_get_addr(struct sk_buff *skb,
1112 				struct genl_info *info);
1113 
1114 static inline u8 subflow_get_local_id(const struct mptcp_subflow_context *subflow)
1115 {
1116 	int local_id = READ_ONCE(subflow->local_id);
1117 
1118 	if (local_id < 0)
1119 		return 0;
1120 	return local_id;
1121 }
1122 
1123 void __init mptcp_pm_nl_init(void);
1124 void mptcp_pm_nl_work(struct mptcp_sock *msk);
1125 void mptcp_pm_nl_rm_subflow_received(struct mptcp_sock *msk,
1126 				     const struct mptcp_rm_list *rm_list);
1127 unsigned int mptcp_pm_get_add_addr_signal_max(const struct mptcp_sock *msk);
1128 unsigned int mptcp_pm_get_add_addr_accept_max(const struct mptcp_sock *msk);
1129 unsigned int mptcp_pm_get_subflows_max(const struct mptcp_sock *msk);
1130 unsigned int mptcp_pm_get_local_addr_max(const struct mptcp_sock *msk);
1131 
1132 /* called under PM lock */
1133 static inline void __mptcp_pm_close_subflow(struct mptcp_sock *msk)
1134 {
1135 	if (--msk->pm.subflows < mptcp_pm_get_subflows_max(msk))
1136 		WRITE_ONCE(msk->pm.accept_subflow, true);
1137 }
1138 
1139 static inline void mptcp_pm_close_subflow(struct mptcp_sock *msk)
1140 {
1141 	spin_lock_bh(&msk->pm.lock);
1142 	__mptcp_pm_close_subflow(msk);
1143 	spin_unlock_bh(&msk->pm.lock);
1144 }
1145 
1146 void mptcp_sockopt_sync(struct mptcp_sock *msk, struct sock *ssk);
1147 void mptcp_sockopt_sync_locked(struct mptcp_sock *msk, struct sock *ssk);
1148 
1149 static inline struct mptcp_ext *mptcp_get_ext(const struct sk_buff *skb)
1150 {
1151 	return (struct mptcp_ext *)skb_ext_find(skb, SKB_EXT_MPTCP);
1152 }
1153 
1154 void mptcp_diag_subflow_init(struct tcp_ulp_ops *ops);
1155 
1156 static inline bool __mptcp_check_fallback(const struct mptcp_sock *msk)
1157 {
1158 	return test_bit(MPTCP_FALLBACK_DONE, &msk->flags);
1159 }
1160 
1161 static inline bool mptcp_check_fallback(const struct sock *sk)
1162 {
1163 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
1164 	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
1165 
1166 	return __mptcp_check_fallback(msk);
1167 }
1168 
1169 static inline void __mptcp_do_fallback(struct mptcp_sock *msk)
1170 {
1171 	if (__mptcp_check_fallback(msk)) {
1172 		pr_debug("TCP fallback already done (msk=%p)", msk);
1173 		return;
1174 	}
1175 	set_bit(MPTCP_FALLBACK_DONE, &msk->flags);
1176 }
1177 
1178 static inline bool __mptcp_has_initial_subflow(const struct mptcp_sock *msk)
1179 {
1180 	struct sock *ssk = READ_ONCE(msk->first);
1181 
1182 	return ssk && ((1 << inet_sk_state_load(ssk)) &
1183 		       (TCPF_ESTABLISHED | TCPF_SYN_SENT |
1184 			TCPF_SYN_RECV | TCPF_LISTEN));
1185 }
1186 
1187 static inline void mptcp_do_fallback(struct sock *ssk)
1188 {
1189 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
1190 	struct sock *sk = subflow->conn;
1191 	struct mptcp_sock *msk;
1192 
1193 	msk = mptcp_sk(sk);
1194 	__mptcp_do_fallback(msk);
1195 	if (READ_ONCE(msk->snd_data_fin_enable) && !(ssk->sk_shutdown & SEND_SHUTDOWN)) {
1196 		gfp_t saved_allocation = ssk->sk_allocation;
1197 
1198 		/* we are in a atomic (BH) scope, override ssk default for data
1199 		 * fin allocation
1200 		 */
1201 		ssk->sk_allocation = GFP_ATOMIC;
1202 		ssk->sk_shutdown |= SEND_SHUTDOWN;
1203 		tcp_shutdown(ssk, SEND_SHUTDOWN);
1204 		ssk->sk_allocation = saved_allocation;
1205 	}
1206 }
1207 
1208 #define pr_fallback(a) pr_debug("%s:fallback to TCP (msk=%p)", __func__, a)
1209 
1210 static inline bool mptcp_check_infinite_map(struct sk_buff *skb)
1211 {
1212 	struct mptcp_ext *mpext;
1213 
1214 	mpext = skb ? mptcp_get_ext(skb) : NULL;
1215 	if (mpext && mpext->infinite_map)
1216 		return true;
1217 
1218 	return false;
1219 }
1220 
1221 static inline bool is_active_ssk(struct mptcp_subflow_context *subflow)
1222 {
1223 	return (subflow->request_mptcp || subflow->request_join);
1224 }
1225 
1226 static inline bool subflow_simultaneous_connect(struct sock *sk)
1227 {
1228 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
1229 
1230 	return (1 << sk->sk_state) &
1231 	       (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2 | TCPF_CLOSING) &&
1232 	       is_active_ssk(subflow) &&
1233 	       !subflow->conn_finished;
1234 }
1235 
1236 #ifdef CONFIG_SYN_COOKIES
1237 void subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
1238 				       struct sk_buff *skb);
1239 bool mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
1240 					struct sk_buff *skb);
1241 void __init mptcp_join_cookie_init(void);
1242 #else
1243 static inline void
1244 subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
1245 				  struct sk_buff *skb) {}
1246 static inline bool
1247 mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
1248 				   struct sk_buff *skb)
1249 {
1250 	return false;
1251 }
1252 
1253 static inline void mptcp_join_cookie_init(void) {}
1254 #endif
1255 
1256 #endif /* __MPTCP_PROTOCOL_H */
1257