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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 
14 #define MPTCP_SUPPORTED_VERSION	1
15 
16 /* MPTCP option bits */
17 #define OPTION_MPTCP_MPC_SYN	BIT(0)
18 #define OPTION_MPTCP_MPC_SYNACK	BIT(1)
19 #define OPTION_MPTCP_MPC_ACK	BIT(2)
20 #define OPTION_MPTCP_MPJ_SYN	BIT(3)
21 #define OPTION_MPTCP_MPJ_SYNACK	BIT(4)
22 #define OPTION_MPTCP_MPJ_ACK	BIT(5)
23 #define OPTION_MPTCP_ADD_ADDR	BIT(6)
24 #define OPTION_MPTCP_ADD_ADDR6	BIT(7)
25 #define OPTION_MPTCP_RM_ADDR	BIT(8)
26 
27 /* MPTCP option subtypes */
28 #define MPTCPOPT_MP_CAPABLE	0
29 #define MPTCPOPT_MP_JOIN	1
30 #define MPTCPOPT_DSS		2
31 #define MPTCPOPT_ADD_ADDR	3
32 #define MPTCPOPT_RM_ADDR	4
33 #define MPTCPOPT_MP_PRIO	5
34 #define MPTCPOPT_MP_FAIL	6
35 #define MPTCPOPT_MP_FASTCLOSE	7
36 
37 /* MPTCP suboption lengths */
38 #define TCPOLEN_MPTCP_MPC_SYN		4
39 #define TCPOLEN_MPTCP_MPC_SYNACK	12
40 #define TCPOLEN_MPTCP_MPC_ACK		20
41 #define TCPOLEN_MPTCP_MPC_ACK_DATA	22
42 #define TCPOLEN_MPTCP_MPJ_SYN		12
43 #define TCPOLEN_MPTCP_MPJ_SYNACK	16
44 #define TCPOLEN_MPTCP_MPJ_ACK		24
45 #define TCPOLEN_MPTCP_DSS_BASE		4
46 #define TCPOLEN_MPTCP_DSS_ACK32		4
47 #define TCPOLEN_MPTCP_DSS_ACK64		8
48 #define TCPOLEN_MPTCP_DSS_MAP32		10
49 #define TCPOLEN_MPTCP_DSS_MAP64		14
50 #define TCPOLEN_MPTCP_DSS_CHECKSUM	2
51 #define TCPOLEN_MPTCP_ADD_ADDR		16
52 #define TCPOLEN_MPTCP_ADD_ADDR_PORT	18
53 #define TCPOLEN_MPTCP_ADD_ADDR_BASE	8
54 #define TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT	10
55 #define TCPOLEN_MPTCP_ADD_ADDR6		28
56 #define TCPOLEN_MPTCP_ADD_ADDR6_PORT	30
57 #define TCPOLEN_MPTCP_ADD_ADDR6_BASE	20
58 #define TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT	22
59 #define TCPOLEN_MPTCP_PORT_LEN		2
60 #define TCPOLEN_MPTCP_RM_ADDR_BASE	4
61 
62 /* MPTCP MP_JOIN flags */
63 #define MPTCPOPT_BACKUP		BIT(0)
64 #define MPTCPOPT_HMAC_LEN	20
65 #define MPTCPOPT_THMAC_LEN	8
66 
67 /* MPTCP MP_CAPABLE flags */
68 #define MPTCP_VERSION_MASK	(0x0F)
69 #define MPTCP_CAP_CHECKSUM_REQD	BIT(7)
70 #define MPTCP_CAP_EXTENSIBILITY	BIT(6)
71 #define MPTCP_CAP_HMAC_SHA256	BIT(0)
72 #define MPTCP_CAP_FLAG_MASK	(0x3F)
73 
74 /* MPTCP DSS flags */
75 #define MPTCP_DSS_DATA_FIN	BIT(4)
76 #define MPTCP_DSS_DSN64		BIT(3)
77 #define MPTCP_DSS_HAS_MAP	BIT(2)
78 #define MPTCP_DSS_ACK64		BIT(1)
79 #define MPTCP_DSS_HAS_ACK	BIT(0)
80 #define MPTCP_DSS_FLAG_MASK	(0x1F)
81 
82 /* MPTCP ADD_ADDR flags */
83 #define MPTCP_ADDR_ECHO		BIT(0)
84 #define MPTCP_ADDR_IPVERSION_4	4
85 #define MPTCP_ADDR_IPVERSION_6	6
86 
87 /* MPTCP socket flags */
88 #define MPTCP_DATA_READY	0
89 #define MPTCP_SEND_SPACE	1
90 #define MPTCP_WORK_RTX		2
91 #define MPTCP_WORK_EOF		3
92 #define MPTCP_FALLBACK_DONE	4
93 #define MPTCP_WORK_CLOSE_SUBFLOW 5
94 
95 struct mptcp_options_received {
96 	u64	sndr_key;
97 	u64	rcvr_key;
98 	u64	data_ack;
99 	u64	data_seq;
100 	u32	subflow_seq;
101 	u16	data_len;
102 	u16	mp_capable : 1,
103 		mp_join : 1,
104 		dss : 1,
105 		add_addr : 1,
106 		rm_addr : 1,
107 		family : 4,
108 		echo : 1,
109 		backup : 1;
110 	u32	token;
111 	u32	nonce;
112 	u64	thmac;
113 	u8	hmac[20];
114 	u8	join_id;
115 	u8	use_map:1,
116 		dsn64:1,
117 		data_fin:1,
118 		use_ack:1,
119 		ack64:1,
120 		mpc_map:1,
121 		__unused:2;
122 	u8	addr_id;
123 	u8	rm_id;
124 	union {
125 		struct in_addr	addr;
126 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
127 		struct in6_addr	addr6;
128 #endif
129 	};
130 	u64	ahmac;
131 	u16	port;
132 };
133 
mptcp_option(u8 subopt,u8 len,u8 nib,u8 field)134 static inline __be32 mptcp_option(u8 subopt, u8 len, u8 nib, u8 field)
135 {
136 	return htonl((TCPOPT_MPTCP << 24) | (len << 16) | (subopt << 12) |
137 		     ((nib & 0xF) << 8) | field);
138 }
139 
140 struct mptcp_addr_info {
141 	sa_family_t		family;
142 	__be16			port;
143 	u8			id;
144 	u8			flags;
145 	int			ifindex;
146 	union {
147 		struct in_addr addr;
148 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
149 		struct in6_addr addr6;
150 #endif
151 	};
152 };
153 
154 enum mptcp_pm_status {
155 	MPTCP_PM_ADD_ADDR_RECEIVED,
156 	MPTCP_PM_RM_ADDR_RECEIVED,
157 	MPTCP_PM_ESTABLISHED,
158 	MPTCP_PM_SUBFLOW_ESTABLISHED,
159 };
160 
161 struct mptcp_pm_data {
162 	struct mptcp_addr_info local;
163 	struct mptcp_addr_info remote;
164 	struct list_head anno_list;
165 
166 	spinlock_t	lock;		/*protects the whole PM data */
167 
168 	bool		add_addr_signal;
169 	bool		rm_addr_signal;
170 	bool		server_side;
171 	bool		work_pending;
172 	bool		accept_addr;
173 	bool		accept_subflow;
174 	bool		add_addr_echo;
175 	u8		add_addr_signaled;
176 	u8		add_addr_accepted;
177 	u8		local_addr_used;
178 	u8		subflows;
179 	u8		add_addr_signal_max;
180 	u8		add_addr_accept_max;
181 	u8		local_addr_max;
182 	u8		subflows_max;
183 	u8		status;
184 	u8		rm_id;
185 };
186 
187 struct mptcp_data_frag {
188 	struct list_head list;
189 	u64 data_seq;
190 	int data_len;
191 	int offset;
192 	int overhead;
193 	struct page *page;
194 };
195 
196 /* MPTCP connection sock */
197 struct mptcp_sock {
198 	/* inet_connection_sock must be the first member */
199 	struct inet_connection_sock sk;
200 	u64		local_key;
201 	u64		remote_key;
202 	u64		write_seq;
203 	u64		ack_seq;
204 	u64		rcv_data_fin_seq;
205 	struct sock	*last_snd;
206 	int		snd_burst;
207 	atomic64_t	snd_una;
208 	unsigned long	timer_ival;
209 	u32		token;
210 	unsigned long	flags;
211 	bool		can_ack;
212 	bool		fully_established;
213 	bool		rcv_data_fin;
214 	bool		snd_data_fin_enable;
215 	bool		use_64bit_ack; /* Set when we received a 64-bit DSN */
216 	spinlock_t	join_list_lock;
217 	struct work_struct work;
218 	struct sk_buff  *ooo_last_skb;
219 	struct rb_root  out_of_order_queue;
220 	struct list_head conn_list;
221 	struct list_head rtx_queue;
222 	struct list_head join_list;
223 	struct skb_ext	*cached_ext;	/* for the next sendmsg */
224 	struct socket	*subflow; /* outgoing connect/listener/!mp_capable */
225 	struct sock	*first;
226 	struct mptcp_pm_data	pm;
227 	struct {
228 		u32	space;	/* bytes copied in last measurement window */
229 		u32	copied; /* bytes copied in this measurement window */
230 		u64	time;	/* start time of measurement window */
231 		u64	rtt_us; /* last maximum rtt of subflows */
232 	} rcvq_space;
233 };
234 
235 #define mptcp_for_each_subflow(__msk, __subflow)			\
236 	list_for_each_entry(__subflow, &((__msk)->conn_list), node)
237 
mptcp_sk(const struct sock * sk)238 static inline struct mptcp_sock *mptcp_sk(const struct sock *sk)
239 {
240 	return (struct mptcp_sock *)sk;
241 }
242 
mptcp_rtx_tail(const struct sock * sk)243 static inline struct mptcp_data_frag *mptcp_rtx_tail(const struct sock *sk)
244 {
245 	struct mptcp_sock *msk = mptcp_sk(sk);
246 
247 	if (list_empty(&msk->rtx_queue))
248 		return NULL;
249 
250 	return list_last_entry(&msk->rtx_queue, struct mptcp_data_frag, list);
251 }
252 
mptcp_rtx_head(const struct sock * sk)253 static inline struct mptcp_data_frag *mptcp_rtx_head(const struct sock *sk)
254 {
255 	struct mptcp_sock *msk = mptcp_sk(sk);
256 
257 	return list_first_entry_or_null(&msk->rtx_queue, struct mptcp_data_frag, list);
258 }
259 
260 struct mptcp_subflow_request_sock {
261 	struct	tcp_request_sock sk;
262 	u16	mp_capable : 1,
263 		mp_join : 1,
264 		backup : 1;
265 	u8	local_id;
266 	u8	remote_id;
267 	u64	local_key;
268 	u64	idsn;
269 	u32	token;
270 	u32	ssn_offset;
271 	u64	thmac;
272 	u32	local_nonce;
273 	u32	remote_nonce;
274 	struct mptcp_sock	*msk;
275 	struct hlist_nulls_node token_node;
276 };
277 
278 static inline struct mptcp_subflow_request_sock *
mptcp_subflow_rsk(const struct request_sock * rsk)279 mptcp_subflow_rsk(const struct request_sock *rsk)
280 {
281 	return (struct mptcp_subflow_request_sock *)rsk;
282 }
283 
284 enum mptcp_data_avail {
285 	MPTCP_SUBFLOW_NODATA,
286 	MPTCP_SUBFLOW_DATA_AVAIL,
287 	MPTCP_SUBFLOW_OOO_DATA
288 };
289 
290 /* MPTCP subflow context */
291 struct mptcp_subflow_context {
292 	struct	list_head node;/* conn_list of subflows */
293 	u64	local_key;
294 	u64	remote_key;
295 	u64	idsn;
296 	u64	map_seq;
297 	u32	snd_isn;
298 	u32	token;
299 	u32	rel_write_seq;
300 	u32	map_subflow_seq;
301 	u32	ssn_offset;
302 	u32	map_data_len;
303 	u32	request_mptcp : 1,  /* send MP_CAPABLE */
304 		request_join : 1,   /* send MP_JOIN */
305 		request_bkup : 1,
306 		mp_capable : 1,	    /* remote is MPTCP capable */
307 		mp_join : 1,	    /* remote is JOINing */
308 		fully_established : 1,	    /* path validated */
309 		pm_notified : 1,    /* PM hook called for established status */
310 		conn_finished : 1,
311 		map_valid : 1,
312 		mpc_map : 1,
313 		backup : 1,
314 		rx_eof : 1,
315 		can_ack : 1;	    /* only after processing the remote a key */
316 	enum mptcp_data_avail data_avail;
317 	u32	remote_nonce;
318 	u64	thmac;
319 	u32	local_nonce;
320 	u32	remote_token;
321 	u8	hmac[MPTCPOPT_HMAC_LEN];
322 	u8	local_id;
323 	u8	remote_id;
324 
325 	struct	sock *tcp_sock;	    /* tcp sk backpointer */
326 	struct	sock *conn;	    /* parent mptcp_sock */
327 	const	struct inet_connection_sock_af_ops *icsk_af_ops;
328 	void	(*tcp_data_ready)(struct sock *sk);
329 	void	(*tcp_state_change)(struct sock *sk);
330 	void	(*tcp_write_space)(struct sock *sk);
331 
332 	struct	rcu_head rcu;
333 };
334 
335 static inline struct mptcp_subflow_context *
mptcp_subflow_ctx(const struct sock * sk)336 mptcp_subflow_ctx(const struct sock *sk)
337 {
338 	struct inet_connection_sock *icsk = inet_csk(sk);
339 
340 	/* Use RCU on icsk_ulp_data only for sock diag code */
341 	return (__force struct mptcp_subflow_context *)icsk->icsk_ulp_data;
342 }
343 
344 static inline struct sock *
mptcp_subflow_tcp_sock(const struct mptcp_subflow_context * subflow)345 mptcp_subflow_tcp_sock(const struct mptcp_subflow_context *subflow)
346 {
347 	return subflow->tcp_sock;
348 }
349 
350 static inline u64
mptcp_subflow_get_map_offset(const struct mptcp_subflow_context * subflow)351 mptcp_subflow_get_map_offset(const struct mptcp_subflow_context *subflow)
352 {
353 	return tcp_sk(mptcp_subflow_tcp_sock(subflow))->copied_seq -
354 		      subflow->ssn_offset -
355 		      subflow->map_subflow_seq;
356 }
357 
358 static inline u64
mptcp_subflow_get_mapped_dsn(const struct mptcp_subflow_context * subflow)359 mptcp_subflow_get_mapped_dsn(const struct mptcp_subflow_context *subflow)
360 {
361 	return subflow->map_seq + mptcp_subflow_get_map_offset(subflow);
362 }
363 
364 int mptcp_is_enabled(struct net *net);
365 void mptcp_subflow_fully_established(struct mptcp_subflow_context *subflow,
366 				     struct mptcp_options_received *mp_opt);
367 bool mptcp_subflow_data_available(struct sock *sk);
368 void __init mptcp_subflow_init(void);
369 void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how);
370 void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
371 		       struct mptcp_subflow_context *subflow,
372 		       long timeout);
373 void mptcp_subflow_reset(struct sock *ssk);
374 
375 /* called with sk socket lock held */
376 int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
377 			    const struct mptcp_addr_info *remote);
378 int mptcp_subflow_create_socket(struct sock *sk, struct socket **new_sock);
379 
mptcp_subflow_tcp_fallback(struct sock * sk,struct mptcp_subflow_context * ctx)380 static inline void mptcp_subflow_tcp_fallback(struct sock *sk,
381 					      struct mptcp_subflow_context *ctx)
382 {
383 	sk->sk_data_ready = ctx->tcp_data_ready;
384 	sk->sk_state_change = ctx->tcp_state_change;
385 	sk->sk_write_space = ctx->tcp_write_space;
386 
387 	inet_csk(sk)->icsk_af_ops = ctx->icsk_af_ops;
388 }
389 
390 void __init mptcp_proto_init(void);
391 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
392 int __init mptcp_proto_v6_init(void);
393 #endif
394 
395 struct sock *mptcp_sk_clone(const struct sock *sk,
396 			    const struct mptcp_options_received *mp_opt,
397 			    struct request_sock *req);
398 void mptcp_get_options(const struct sk_buff *skb,
399 		       struct mptcp_options_received *mp_opt);
400 
401 void mptcp_finish_connect(struct sock *sk);
mptcp_is_fully_established(struct sock * sk)402 static inline bool mptcp_is_fully_established(struct sock *sk)
403 {
404 	return inet_sk_state_load(sk) == TCP_ESTABLISHED &&
405 	       READ_ONCE(mptcp_sk(sk)->fully_established);
406 }
407 void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk);
408 void mptcp_data_ready(struct sock *sk, struct sock *ssk);
409 bool mptcp_finish_join(struct sock *sk);
410 void mptcp_data_acked(struct sock *sk);
411 void mptcp_subflow_eof(struct sock *sk);
412 bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit);
413 void mptcp_destroy_common(struct mptcp_sock *msk);
414 
415 void __init mptcp_token_init(void);
mptcp_token_init_request(struct request_sock * req)416 static inline void mptcp_token_init_request(struct request_sock *req)
417 {
418 	mptcp_subflow_rsk(req)->token_node.pprev = NULL;
419 }
420 
421 int mptcp_token_new_request(struct request_sock *req);
422 void mptcp_token_destroy_request(struct request_sock *req);
423 int mptcp_token_new_connect(struct sock *sk);
424 void mptcp_token_accept(struct mptcp_subflow_request_sock *r,
425 			struct mptcp_sock *msk);
426 bool mptcp_token_exists(u32 token);
427 struct mptcp_sock *mptcp_token_get_sock(struct net *net, u32 token);
428 struct mptcp_sock *mptcp_token_iter_next(const struct net *net, long *s_slot,
429 					 long *s_num);
430 void mptcp_token_destroy(struct mptcp_sock *msk);
431 
432 void mptcp_crypto_key_sha(u64 key, u32 *token, u64 *idsn);
433 
434 void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u8 *msg, int len, void *hmac);
435 
436 void __init mptcp_pm_init(void);
437 void mptcp_pm_data_init(struct mptcp_sock *msk);
438 void mptcp_pm_new_connection(struct mptcp_sock *msk, int server_side);
439 void mptcp_pm_fully_established(struct mptcp_sock *msk);
440 bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk);
441 void mptcp_pm_connection_closed(struct mptcp_sock *msk);
442 void mptcp_pm_subflow_established(struct mptcp_sock *msk,
443 				  struct mptcp_subflow_context *subflow);
444 void mptcp_pm_subflow_closed(struct mptcp_sock *msk, u8 id);
445 void mptcp_pm_add_addr_received(struct mptcp_sock *msk,
446 				const struct mptcp_addr_info *addr);
447 void mptcp_pm_rm_addr_received(struct mptcp_sock *msk, u8 rm_id);
448 void mptcp_pm_free_anno_list(struct mptcp_sock *msk);
449 struct mptcp_pm_add_entry *
450 mptcp_pm_del_add_timer(struct mptcp_sock *msk,
451 		       struct mptcp_addr_info *addr);
452 
453 int mptcp_pm_announce_addr(struct mptcp_sock *msk,
454 			   const struct mptcp_addr_info *addr,
455 			   bool echo);
456 int mptcp_pm_remove_addr(struct mptcp_sock *msk, u8 local_id);
457 int mptcp_pm_remove_subflow(struct mptcp_sock *msk, u8 local_id);
458 
mptcp_pm_should_add_signal(struct mptcp_sock * msk)459 static inline bool mptcp_pm_should_add_signal(struct mptcp_sock *msk)
460 {
461 	return READ_ONCE(msk->pm.add_addr_signal);
462 }
463 
mptcp_pm_should_rm_signal(struct mptcp_sock * msk)464 static inline bool mptcp_pm_should_rm_signal(struct mptcp_sock *msk)
465 {
466 	return READ_ONCE(msk->pm.rm_addr_signal);
467 }
468 
mptcp_add_addr_len(int family,bool echo)469 static inline unsigned int mptcp_add_addr_len(int family, bool echo)
470 {
471 	if (family == AF_INET)
472 		return echo ? TCPOLEN_MPTCP_ADD_ADDR_BASE
473 			    : TCPOLEN_MPTCP_ADD_ADDR;
474 	return echo ? TCPOLEN_MPTCP_ADD_ADDR6_BASE : TCPOLEN_MPTCP_ADD_ADDR6;
475 }
476 
477 bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
478 			      struct mptcp_addr_info *saddr, bool *echo);
479 bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
480 			     u8 *rm_id);
481 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
482 
483 void __init mptcp_pm_nl_init(void);
484 void mptcp_pm_nl_data_init(struct mptcp_sock *msk);
485 void mptcp_pm_nl_fully_established(struct mptcp_sock *msk);
486 void mptcp_pm_nl_subflow_established(struct mptcp_sock *msk);
487 void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk);
488 void mptcp_pm_nl_rm_addr_received(struct mptcp_sock *msk);
489 void mptcp_pm_nl_rm_subflow_received(struct mptcp_sock *msk, u8 rm_id);
490 int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
491 
mptcp_get_ext(struct sk_buff * skb)492 static inline struct mptcp_ext *mptcp_get_ext(struct sk_buff *skb)
493 {
494 	return (struct mptcp_ext *)skb_ext_find(skb, SKB_EXT_MPTCP);
495 }
496 
before64(__u64 seq1,__u64 seq2)497 static inline bool before64(__u64 seq1, __u64 seq2)
498 {
499 	return (__s64)(seq1 - seq2) < 0;
500 }
501 
502 #define after64(seq2, seq1)	before64(seq1, seq2)
503 
504 void mptcp_diag_subflow_init(struct tcp_ulp_ops *ops);
505 
__mptcp_check_fallback(const struct mptcp_sock * msk)506 static inline bool __mptcp_check_fallback(const struct mptcp_sock *msk)
507 {
508 	return test_bit(MPTCP_FALLBACK_DONE, &msk->flags);
509 }
510 
mptcp_check_fallback(const struct sock * sk)511 static inline bool mptcp_check_fallback(const struct sock *sk)
512 {
513 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
514 	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
515 
516 	return __mptcp_check_fallback(msk);
517 }
518 
__mptcp_do_fallback(struct mptcp_sock * msk)519 static inline void __mptcp_do_fallback(struct mptcp_sock *msk)
520 {
521 	if (test_bit(MPTCP_FALLBACK_DONE, &msk->flags)) {
522 		pr_debug("TCP fallback already done (msk=%p)", msk);
523 		return;
524 	}
525 	set_bit(MPTCP_FALLBACK_DONE, &msk->flags);
526 }
527 
mptcp_do_fallback(struct sock * sk)528 static inline void mptcp_do_fallback(struct sock *sk)
529 {
530 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
531 	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
532 
533 	__mptcp_do_fallback(msk);
534 }
535 
536 #define pr_fallback(a) pr_debug("%s:fallback to TCP (msk=%p)", __func__, a)
537 
subflow_simultaneous_connect(struct sock * sk)538 static inline bool subflow_simultaneous_connect(struct sock *sk)
539 {
540 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
541 	struct sock *parent = subflow->conn;
542 
543 	return sk->sk_state == TCP_ESTABLISHED &&
544 	       !mptcp_sk(parent)->pm.server_side &&
545 	       !subflow->conn_finished;
546 }
547 
548 #ifdef CONFIG_SYN_COOKIES
549 void subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
550 				       struct sk_buff *skb);
551 bool mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
552 					struct sk_buff *skb);
553 void __init mptcp_join_cookie_init(void);
554 #else
555 static inline void
subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock * subflow_req,struct sk_buff * skb)556 subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
557 				  struct sk_buff *skb) {}
558 static inline bool
mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock * subflow_req,struct sk_buff * skb)559 mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
560 				   struct sk_buff *skb)
561 {
562 	return false;
563 }
564 
mptcp_join_cookie_init(void)565 static inline void mptcp_join_cookie_init(void) {}
566 #endif
567 
568 #endif /* __MPTCP_PROTOCOL_H */
569