[linux-2.6-block.git] / net / mptcp / protocol.h

/* SPDX-License-Identifier: GPL-2.0 */
/* Multipath TCP
 *
 * Copyright (c) 2017 - 2019, Intel Corporation.
 */

#ifndef __MPTCP_PROTOCOL_H
#define __MPTCP_PROTOCOL_H

#include <linux/random.h>
#include <net/tcp.h>
#include <net/inet_connection_sock.h>

#define MPTCP_SUPPORTED_VERSION	1

/* MPTCP option bits */
#define OPTION_MPTCP_MPC_SYN	BIT(0)
#define OPTION_MPTCP_MPC_SYNACK	BIT(1)
#define OPTION_MPTCP_MPC_ACK	BIT(2)

/* MPTCP option subtypes */
#define MPTCPOPT_MP_CAPABLE	0
#define MPTCPOPT_MP_JOIN	1
#define MPTCPOPT_DSS		2
#define MPTCPOPT_ADD_ADDR	3
#define MPTCPOPT_RM_ADDR	4
#define MPTCPOPT_MP_PRIO	5
#define MPTCPOPT_MP_FAIL	6
#define MPTCPOPT_MP_FASTCLOSE	7

/* MPTCP suboption lengths */
#define TCPOLEN_MPTCP_MPC_SYN		4
#define TCPOLEN_MPTCP_MPC_SYNACK	12
#define TCPOLEN_MPTCP_MPC_ACK		20
#define TCPOLEN_MPTCP_MPC_ACK_DATA	22
#define TCPOLEN_MPTCP_DSS_BASE		4
#define TCPOLEN_MPTCP_DSS_ACK32		4
#define TCPOLEN_MPTCP_DSS_ACK64		8
#define TCPOLEN_MPTCP_DSS_MAP32		10
#define TCPOLEN_MPTCP_DSS_MAP64		14
#define TCPOLEN_MPTCP_DSS_CHECKSUM	2

/* MPTCP MP_CAPABLE flags */
#define MPTCP_VERSION_MASK	(0x0F)
#define MPTCP_CAP_CHECKSUM_REQD	BIT(7)
#define MPTCP_CAP_EXTENSIBILITY	BIT(6)
#define MPTCP_CAP_HMAC_SHA256	BIT(0)
#define MPTCP_CAP_FLAG_MASK	(0x3F)

/* MPTCP DSS flags */
#define MPTCP_DSS_DATA_FIN	BIT(4)
#define MPTCP_DSS_DSN64		BIT(3)
#define MPTCP_DSS_HAS_MAP	BIT(2)
#define MPTCP_DSS_ACK64		BIT(1)
#define MPTCP_DSS_HAS_ACK	BIT(0)
#define MPTCP_DSS_FLAG_MASK	(0x1F)

/* MPTCP socket flags */
#define MPTCP_DATA_READY	BIT(0)
#define MPTCP_SEND_SPACE	BIT(1)

/* MPTCP connection sock */
struct mptcp_sock {
	/* inet_connection_sock must be the first member */
	struct inet_connection_sock sk;
	u64		local_key;
	u64		remote_key;
	u64		write_seq;
	u64		ack_seq;
	u32		token;
	unsigned long	flags;
	bool		can_ack;
	struct list_head conn_list;
	struct skb_ext	*cached_ext;	/* for the next sendmsg */
	struct socket	*subflow; /* outgoing connect/listener/!mp_capable */
	struct sock	*first;
};

#define mptcp_for_each_subflow(__msk, __subflow)			\
	list_for_each_entry(__subflow, &((__msk)->conn_list), node)

static inline struct mptcp_sock *mptcp_sk(const struct sock *sk)
{
	return (struct mptcp_sock *)sk;
}

struct mptcp_subflow_request_sock {
	struct	tcp_request_sock sk;
	u16	mp_capable : 1,
		mp_join : 1,
		backup : 1,
		remote_key_valid : 1;
	u64	local_key;
	u64	remote_key;
	u64	idsn;
	u32	token;
	u32	ssn_offset;
};

static inline struct mptcp_subflow_request_sock *
mptcp_subflow_rsk(const struct request_sock *rsk)
{
	return (struct mptcp_subflow_request_sock *)rsk;
}

/* MPTCP subflow context */
struct mptcp_subflow_context {
	struct	list_head node;/* conn_list of subflows */
	u64	local_key;
	u64	remote_key;
	u64	idsn;
	u64	map_seq;
	u32	snd_isn;
	u32	token;
	u32	rel_write_seq;
	u32	map_subflow_seq;
	u32	ssn_offset;
	u32	map_data_len;
	u32	request_mptcp : 1,  /* send MP_CAPABLE */
		mp_capable : 1,	    /* remote is MPTCP capable */
		fourth_ack : 1,	    /* send initial DSS */
		conn_finished : 1,
		map_valid : 1,
		mpc_map : 1,
		data_avail : 1,
		rx_eof : 1,
		can_ack : 1;	    /* only after processing the remote a key */

	struct	sock *tcp_sock;	    /* tcp sk backpointer */
	struct	sock *conn;	    /* parent mptcp_sock */
	const	struct inet_connection_sock_af_ops *icsk_af_ops;
	void	(*tcp_data_ready)(struct sock *sk);
	void	(*tcp_state_change)(struct sock *sk);
	void	(*tcp_write_space)(struct sock *sk);

	struct	rcu_head rcu;
};

static inline struct mptcp_subflow_context *
mptcp_subflow_ctx(const struct sock *sk)
{
	struct inet_connection_sock *icsk = inet_csk(sk);

	/* Use RCU on icsk_ulp_data only for sock diag code */
	return (__force struct mptcp_subflow_context *)icsk->icsk_ulp_data;
}

static inline struct sock *
mptcp_subflow_tcp_sock(const struct mptcp_subflow_context *subflow)
{
	return subflow->tcp_sock;
}

static inline u64
mptcp_subflow_get_map_offset(const struct mptcp_subflow_context *subflow)
{
	return tcp_sk(mptcp_subflow_tcp_sock(subflow))->copied_seq -
		      subflow->ssn_offset -
		      subflow->map_subflow_seq;
}

static inline u64
mptcp_subflow_get_mapped_dsn(const struct mptcp_subflow_context *subflow)
{
	return subflow->map_seq + mptcp_subflow_get_map_offset(subflow);
}

int mptcp_is_enabled(struct net *net);
bool mptcp_subflow_data_available(struct sock *sk);
void mptcp_subflow_init(void);
int mptcp_subflow_create_socket(struct sock *sk, struct socket **new_sock);

static inline void mptcp_subflow_tcp_fallback(struct sock *sk,
					      struct mptcp_subflow_context *ctx)
{
	sk->sk_data_ready = ctx->tcp_data_ready;
	sk->sk_state_change = ctx->tcp_state_change;
	sk->sk_write_space = ctx->tcp_write_space;

	inet_csk(sk)->icsk_af_ops = ctx->icsk_af_ops;
}

extern const struct inet_connection_sock_af_ops ipv4_specific;
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
extern const struct inet_connection_sock_af_ops ipv6_specific;
#endif

void mptcp_proto_init(void);
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
int mptcp_proto_v6_init(void);
#endif

struct mptcp_read_arg {
	struct msghdr *msg;
};

int mptcp_read_actor(read_descriptor_t *desc, struct sk_buff *skb,
		     unsigned int offset, size_t len);

void mptcp_get_options(const struct sk_buff *skb,
		       struct tcp_options_received *opt_rx);

void mptcp_finish_connect(struct sock *sk);

int mptcp_token_new_request(struct request_sock *req);
void mptcp_token_destroy_request(u32 token);
int mptcp_token_new_connect(struct sock *sk);
int mptcp_token_new_accept(u32 token);
void mptcp_token_update_accept(struct sock *sk, struct sock *conn);
void mptcp_token_destroy(u32 token);

void mptcp_crypto_key_sha(u64 key, u32 *token, u64 *idsn);
static inline void mptcp_crypto_key_gen_sha(u64 *key, u32 *token, u64 *idsn)
{
	/* we might consider a faster version that computes the key as a
	 * hash of some information available in the MPTCP socket. Use
	 * random data at the moment, as it's probably the safest option
	 * in case multiple sockets are opened in different namespaces at
	 * the same time.
	 */
	get_random_bytes(key, sizeof(u64));
	mptcp_crypto_key_sha(*key, token, idsn);
}

void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u32 nonce1, u32 nonce2,
			   void *hash_out);

static inline struct mptcp_ext *mptcp_get_ext(struct sk_buff *skb)
{
	return (struct mptcp_ext *)skb_ext_find(skb, SKB_EXT_MPTCP);
}

static inline bool before64(__u64 seq1, __u64 seq2)
{
	return (__s64)(seq1 - seq2) < 0;
}

#define after64(seq2, seq1)	before64(seq1, seq2)

#endif /* __MPTCP_PROTOCOL_H */
Commit	Line	Data
f870fa0b MM	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
79c0949e PK	10	#include <linux/random.h>
	11	#include <net/tcp.h>
	12	#include <net/inet_connection_sock.h>
	13
cc7972ea	14	#define MPTCP_SUPPORTED_VERSION 1
eda7acdd PK	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
	21	/* MPTCP option subtypes */
	22	#define MPTCPOPT_MP_CAPABLE 0
	23	#define MPTCPOPT_MP_JOIN 1
	24	#define MPTCPOPT_DSS 2
	25	#define MPTCPOPT_ADD_ADDR 3
	26	#define MPTCPOPT_RM_ADDR 4
	27	#define MPTCPOPT_MP_PRIO 5
	28	#define MPTCPOPT_MP_FAIL 6
	29	#define MPTCPOPT_MP_FASTCLOSE 7
	30
	31	/* MPTCP suboption lengths */
cc7972ea	32	#define TCPOLEN_MPTCP_MPC_SYN 4
eda7acdd PK	33	#define TCPOLEN_MPTCP_MPC_SYNACK 12
eda7acdd PK	34	#define TCPOLEN_MPTCP_MPC_ACK 20
cc7972ea	35	#define TCPOLEN_MPTCP_MPC_ACK_DATA 22
6d0060f6	36	#define TCPOLEN_MPTCP_DSS_BASE 4
648ef4b8	37	#define TCPOLEN_MPTCP_DSS_ACK32 4
6d0060f6	38	#define TCPOLEN_MPTCP_DSS_ACK64 8
648ef4b8	39	#define TCPOLEN_MPTCP_DSS_MAP32 10
6d0060f6 MM	40	#define TCPOLEN_MPTCP_DSS_MAP64 14
6d0060f6 MM	41	#define TCPOLEN_MPTCP_DSS_CHECKSUM 2
eda7acdd PK	42
	43	/* MPTCP MP_CAPABLE flags */
	44	#define MPTCP_VERSION_MASK (0x0F)
	45	#define MPTCP_CAP_CHECKSUM_REQD BIT(7)
	46	#define MPTCP_CAP_EXTENSIBILITY BIT(6)
65492c5a	47	#define MPTCP_CAP_HMAC_SHA256 BIT(0)
eda7acdd PK	48	#define MPTCP_CAP_FLAG_MASK (0x3F)
eda7acdd PK	49
6d0060f6 MM	50	/* MPTCP DSS flags */
	51	#define MPTCP_DSS_DATA_FIN BIT(4)
	52	#define MPTCP_DSS_DSN64 BIT(3)
	53	#define MPTCP_DSS_HAS_MAP BIT(2)
	54	#define MPTCP_DSS_ACK64 BIT(1)
	55	#define MPTCP_DSS_HAS_ACK BIT(0)
648ef4b8 MM	56	#define MPTCP_DSS_FLAG_MASK (0x1F)
	57
	58	/* MPTCP socket flags */
	59	#define MPTCP_DATA_READY BIT(0)
1891c4a0	60	#define MPTCP_SEND_SPACE BIT(1)
6d0060f6	61
f870fa0b MM	62	/* MPTCP connection sock */
	63	struct mptcp_sock {
	64	/* inet_connection_sock must be the first member */
	65	struct inet_connection_sock sk;
cec37a6e PK	66	u64 local_key;
cec37a6e PK	67	u64 remote_key;
6d0060f6 MM	68	u64 write_seq;
6d0060f6 MM	69	u64 ack_seq;
79c0949e	70	u32 token;
648ef4b8	71	unsigned long flags;
d22f4988	72	bool can_ack;
cec37a6e	73	struct list_head conn_list;
6d0060f6	74	struct skb_ext cached_ext; / for the next sendmsg */
f870fa0b	75	struct socket subflow; / outgoing connect/listener/!mp_capable */
8ab183de	76	struct sock *first;
f870fa0b MM	77	};
f870fa0b MM	78
cec37a6e PK	79	#define mptcp_for_each_subflow(__msk, __subflow) \
	80	list_for_each_entry(__subflow, &((__msk)->conn_list), node)
	81
f870fa0b MM	82	static inline struct mptcp_sock mptcp_sk(const struct sock sk)
	83	{
	84	return (struct mptcp_sock *)sk;
	85	}
	86
cec37a6e PK	87	struct mptcp_subflow_request_sock {
cec37a6e PK	88	struct tcp_request_sock sk;
d22f4988	89	u16 mp_capable : 1,
cec37a6e	90	mp_join : 1,
d22f4988 CP	91	backup : 1,
d22f4988 CP	92	remote_key_valid : 1;
cec37a6e PK	93	u64 local_key;
cec37a6e PK	94	u64 remote_key;
79c0949e PK	95	u64 idsn;
79c0949e PK	96	u32 token;
648ef4b8	97	u32 ssn_offset;
cec37a6e PK	98	};
	99
	100	static inline struct mptcp_subflow_request_sock *
	101	mptcp_subflow_rsk(const struct request_sock *rsk)
	102	{
	103	return (struct mptcp_subflow_request_sock *)rsk;
	104	}
	105
2303f994 PK	106	/* MPTCP subflow context */
2303f994 PK	107	struct mptcp_subflow_context {
cec37a6e PK	108	struct list_head node;/* conn_list of subflows */
	109	u64 local_key;
	110	u64 remote_key;
79c0949e	111	u64 idsn;
648ef4b8	112	u64 map_seq;
cc7972ea	113	u32 snd_isn;
79c0949e	114	u32 token;
6d0060f6	115	u32 rel_write_seq;
648ef4b8 MM	116	u32 map_subflow_seq;
	117	u32 ssn_offset;
	118	u32 map_data_len;
cec37a6e PK	119	u32 request_mptcp : 1, /* send MP_CAPABLE */
	120	mp_capable : 1, /* remote is MPTCP capable */
	121	fourth_ack : 1, /* send initial DSS */
648ef4b8 MM	122	conn_finished : 1,
648ef4b8 MM	123	map_valid : 1,
d22f4988	124	mpc_map : 1,
648ef4b8	125	data_avail : 1,
d22f4988 CP	126	rx_eof : 1,
d22f4988 CP	127	can_ack : 1; /* only after processing the remote a key */
648ef4b8	128
2303f994 PK	129	struct sock tcp_sock; / tcp sk backpointer */
2303f994 PK	130	struct sock conn; / parent mptcp_sock */
cec37a6e	131	const struct inet_connection_sock_af_ops *icsk_af_ops;
648ef4b8 MM	132	void (tcp_data_ready)(struct sock sk);
	133	void (tcp_state_change)(struct sock sk);
	134	void (tcp_write_space)(struct sock sk);
	135
2303f994 PK	136	struct rcu_head rcu;
	137	};
	138
	139	static inline struct mptcp_subflow_context *
	140	mptcp_subflow_ctx(const struct sock *sk)
	141	{
	142	struct inet_connection_sock *icsk = inet_csk(sk);
	143
	144	/* Use RCU on icsk_ulp_data only for sock diag code */
	145	return (__force struct mptcp_subflow_context *)icsk->icsk_ulp_data;
	146	}
	147
	148	static inline struct sock *
	149	mptcp_subflow_tcp_sock(const struct mptcp_subflow_context *subflow)
	150	{
	151	return subflow->tcp_sock;
	152	}
	153
648ef4b8 MM	154	static inline u64
	155	mptcp_subflow_get_map_offset(const struct mptcp_subflow_context *subflow)
	156	{
	157	return tcp_sk(mptcp_subflow_tcp_sock(subflow))->copied_seq -
	158	subflow->ssn_offset -
	159	subflow->map_subflow_seq;
	160	}
	161
	162	static inline u64
	163	mptcp_subflow_get_mapped_dsn(const struct mptcp_subflow_context *subflow)
	164	{
	165	return subflow->map_seq + mptcp_subflow_get_map_offset(subflow);
	166	}
	167
	168	int mptcp_is_enabled(struct net *net);
	169	bool mptcp_subflow_data_available(struct sock *sk);
2303f994 PK	170	void mptcp_subflow_init(void);
	171	int mptcp_subflow_create_socket(struct sock sk, struct socket *new_sock);
	172
648ef4b8 MM	173	static inline void mptcp_subflow_tcp_fallback(struct sock *sk,
	174	struct mptcp_subflow_context *ctx)
	175	{
	176	sk->sk_data_ready = ctx->tcp_data_ready;
	177	sk->sk_state_change = ctx->tcp_state_change;
	178	sk->sk_write_space = ctx->tcp_write_space;
	179
	180	inet_csk(sk)->icsk_af_ops = ctx->icsk_af_ops;
	181	}
	182
cec37a6e PK	183	extern const struct inet_connection_sock_af_ops ipv4_specific;
	184	#if IS_ENABLED(CONFIG_MPTCP_IPV6)
	185	extern const struct inet_connection_sock_af_ops ipv6_specific;
	186	#endif
	187
648ef4b8	188	void mptcp_proto_init(void);
784325e9 MB	189	#if IS_ENABLED(CONFIG_MPTCP_IPV6)
	190	int mptcp_proto_v6_init(void);
	191	#endif
648ef4b8 MM	192
	193	struct mptcp_read_arg {
	194	struct msghdr *msg;
	195	};
	196
	197	int mptcp_read_actor(read_descriptor_t desc, struct sk_buff skb,
	198	unsigned int offset, size_t len);
	199
cec37a6e PK	200	void mptcp_get_options(const struct sk_buff *skb,
	201	struct tcp_options_received *opt_rx);
	202
	203	void mptcp_finish_connect(struct sock *sk);
	204
79c0949e PK	205	int mptcp_token_new_request(struct request_sock *req);
	206	void mptcp_token_destroy_request(u32 token);
	207	int mptcp_token_new_connect(struct sock *sk);
	208	int mptcp_token_new_accept(u32 token);
	209	void mptcp_token_update_accept(struct sock sk, struct sock conn);
	210	void mptcp_token_destroy(u32 token);
	211
	212	void mptcp_crypto_key_sha(u64 key, u32 token, u64 idsn);
	213	static inline void mptcp_crypto_key_gen_sha(u64 key, u32 token, u64 *idsn)
	214	{
	215	/* we might consider a faster version that computes the key as a
	216	* hash of some information available in the MPTCP socket. Use
	217	* random data at the moment, as it's probably the safest option
	218	* in case multiple sockets are opened in different namespaces at
	219	* the same time.
	220	*/
	221	get_random_bytes(key, sizeof(u64));
	222	mptcp_crypto_key_sha(*key, token, idsn);
	223	}
	224
	225	void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u32 nonce1, u32 nonce2,
65492c5a	226	void *hash_out);
79c0949e	227
6d0060f6 MM	228	static inline struct mptcp_ext mptcp_get_ext(struct sk_buff skb)
	229	{
	230	return (struct mptcp_ext *)skb_ext_find(skb, SKB_EXT_MPTCP);
	231	}
	232
648ef4b8 MM	233	static inline bool before64(__u64 seq1, __u64 seq2)
	234	{
	235	return (__s64)(seq1 - seq2) < 0;
	236	}
	237
	238	#define after64(seq2, seq1) before64(seq1, seq2)
	239
f870fa0b	240	#endif /* __MPTCP_PROTOCOL_H */