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/* 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 0
#define MPTCP_SEND_SPACE 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 work_struct work;
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
void mptcp_get_options(const struct sk_buff *skb,
struct tcp_options_received *opt_rx);
void mptcp_finish_connect(struct sock *sk);
void mptcp_data_ready(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 */
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