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