linux/include/net/mptcp.h

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

#ifndef __NET_MPTCP_H
#define __NET_MPTCP_H

#include <linux/skbuff.h>
#include <linux/tcp.h>
#include <linux/types.h>

struct mptcp_info;
struct mptcp_sock;
struct seq_file;

/* MPTCP sk_buff extension data */
struct mptcp_ext { … };

#define MPTCPOPT_HMAC_LEN …
#define MPTCP_RM_IDS_MAX …

struct mptcp_rm_list { … };

struct mptcp_addr_info { … };

struct mptcp_out_options { … };

#define MPTCP_SCHED_NAME_MAX …
#define MPTCP_SCHED_MAX …
#define MPTCP_SCHED_BUF_MAX …

#define MPTCP_SUBFLOWS_MAX …

struct mptcp_sched_data { … };

struct mptcp_sched_ops { … } ____cacheline_aligned_in_smp;

#ifdef CONFIG_MPTCP
void mptcp_init(void);

static inline bool sk_is_mptcp(const struct sock *sk)
{ … }

static inline bool rsk_is_mptcp(const struct request_sock *req)
{ … }

static inline bool rsk_drop_req(const struct request_sock *req)
{ … }

void mptcp_space(const struct sock *ssk, int *space, int *full_space);
bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
		       unsigned int *size, struct mptcp_out_options *opts);
bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,
			  struct mptcp_out_options *opts);
bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
			       unsigned int *size, unsigned int remaining,
			       struct mptcp_out_options *opts);
bool mptcp_incoming_options(struct sock *sk, struct sk_buff *skb);

void mptcp_write_options(struct tcphdr *th, __be32 *ptr, struct tcp_sock *tp,
			 struct mptcp_out_options *opts);

void mptcp_diag_fill_info(struct mptcp_sock *msk, struct mptcp_info *info);

/* move the skb extension owership, with the assumption that 'to' is
 * newly allocated
 */
static inline void mptcp_skb_ext_move(struct sk_buff *to,
				      struct sk_buff *from)
{ … }

static inline void mptcp_skb_ext_copy(struct sk_buff *to,
				      struct sk_buff *from)
{ … }

static inline bool mptcp_ext_matches(const struct mptcp_ext *to_ext,
				     const struct mptcp_ext *from_ext)
{ … }

/* check if skbs can be collapsed.
 * MPTCP collapse is allowed if neither @to or @from carry an mptcp data
 * mapping, or if the extension of @to is the same as @from.
 * Collapsing is not possible if @to lacks an extension, but @from carries one.
 */
static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
					  const struct sk_buff *from)
{ … }

void mptcp_seq_show(struct seq_file *seq);
int mptcp_subflow_init_cookie_req(struct request_sock *req,
				  const struct sock *sk_listener,
				  struct sk_buff *skb);
struct request_sock *mptcp_subflow_reqsk_alloc(const struct request_sock_ops *ops,
					       struct sock *sk_listener,
					       bool attach_listener);

__be32 mptcp_get_reset_option(const struct sk_buff *skb);

static inline __be32 mptcp_reset_option(const struct sk_buff *skb)
{ … }
#else

static inline void mptcp_init(void)
{
}

static inline bool sk_is_mptcp(const struct sock *sk)
{
	return false;
}

static inline bool rsk_is_mptcp(const struct request_sock *req)
{
	return false;
}

static inline bool rsk_drop_req(const struct request_sock *req)
{
	return false;
}

static inline bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
				     unsigned int *size,
				     struct mptcp_out_options *opts)
{
	return false;
}

static inline bool mptcp_synack_options(const struct request_sock *req,
					unsigned int *size,
					struct mptcp_out_options *opts)
{
	return false;
}

static inline bool mptcp_established_options(struct sock *sk,
					     struct sk_buff *skb,
					     unsigned int *size,
					     unsigned int remaining,
					     struct mptcp_out_options *opts)
{
	return false;
}

static inline bool mptcp_incoming_options(struct sock *sk,
					  struct sk_buff *skb)
{
	return true;
}

static inline void mptcp_skb_ext_move(struct sk_buff *to,
				      const struct sk_buff *from)
{
}

static inline void mptcp_skb_ext_copy(struct sk_buff *to,
				      struct sk_buff *from)
{
}

static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
					  const struct sk_buff *from)
{
	return true;
}

static inline void mptcp_space(const struct sock *ssk, int *s, int *fs) { }
static inline void mptcp_seq_show(struct seq_file *seq) { }

static inline int mptcp_subflow_init_cookie_req(struct request_sock *req,
						const struct sock *sk_listener,
						struct sk_buff *skb)
{
	return 0; /* TCP fallback */
}

static inline struct request_sock *mptcp_subflow_reqsk_alloc(const struct request_sock_ops *ops,
							     struct sock *sk_listener,
							     bool attach_listener)
{
	return NULL;
}

static inline __be32 mptcp_reset_option(const struct sk_buff *skb)  { return htonl(0u); }
#endif /* CONFIG_MPTCP */

#if IS_ENABLED(CONFIG_MPTCP_IPV6)
int mptcpv6_init(void);
void mptcpv6_handle_mapped(struct sock *sk, bool mapped);
#elif IS_ENABLED(CONFIG_IPV6)
static inline int mptcpv6_init(void) { return 0; }
static inline void mptcpv6_handle_mapped(struct sock *sk, bool mapped) { }
#endif

#if defined(CONFIG_MPTCP) && defined(CONFIG_BPF_SYSCALL)
struct mptcp_sock *bpf_mptcp_sock_from_subflow(struct sock *sk);
#else
static inline struct mptcp_sock *bpf_mptcp_sock_from_subflow(struct sock *sk) { return NULL; }
#endif

#if !IS_ENABLED(CONFIG_MPTCP)
struct mptcp_sock { };
#endif

#endif /* __NET_MPTCP_H */