include/net/mptcp.h

File Facts

System

Linux kernel

Corpus path

include/net/mptcp.h

Extension

.h

Size

7889 bytes

Lines

336

Domain

Networking Core

Bucket

Sockets, Protocols, Packet Path, And Network Policy

Inferred role

Networking Core: implementation source

Status

source implementation candidate

Why This File Exists

Networking stack implementation surface: socket APIs, protocol dispatch, packet flow, routing, filtering, and network namespaces.

• Networking stack implementation surface: socket APIs, protocol dispatch, packet flow, routing, filtering, and network namespaces.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• linux/skbuff.h
• linux/tcp.h
• linux/types.h

Detected Declarations

• struct mptcp_info
• struct mptcp_sock
• struct mptcp_pm_addr_entry
• struct seq_file
• struct mptcp_ext
• struct mptcp_rm_list
• struct mptcp_addr_info
• struct mptcp_out_options
• struct mptcp_sched_ops
• struct mptcp_pm_ops
• struct mptcp_sock
• function sk_is_mptcp
• function rsk_is_mptcp
• function rsk_drop_req
• function mptcp_skb_ext_move
• function mptcp_skb_ext_copy
• function mptcp_ext_matches
• function mptcp_skb_can_collapse
• function mptcp_reset_option
• function mptcp_init
• function rsk_is_mptcp
• function rsk_drop_req
• function mptcp_syn_options
• function mptcp_synack_options
• function mptcp_incoming_options
• function mptcp_skb_ext_move
• function mptcp_space
• function mptcp_reset_option
• function mptcp_active_detect_blackhole
• function mptcpv6_init
• function mptcpv6_handle_mapped

Annotated Snippet

struct mptcp_ext {
	union {
		u64	data_ack;
		u32	data_ack32;
	};
	u64		data_seq;
	u32		subflow_seq;
	u16		data_len;
	__sum16		csum;

	struct_group(flags,
		u8	use_map:1,
			dsn64:1,
			data_fin:1,
			use_ack:1,
			ack64:1,
			mpc_map:1,
			frozen:1,
			reset_transient:1;
		u8	reset_reason:4,
			csum_reqd:1,
			infinite_map:1;
	); /* end of flags group */
};

#define MPTCPOPT_HMAC_LEN	20
#define MPTCP_RM_IDS_MAX	8

struct mptcp_rm_list {
	u8 ids[MPTCP_RM_IDS_MAX];
	u8 nr;
};

struct mptcp_addr_info {
	u8			id;
	sa_family_t		family;
	__be16			port;
	union {
		struct in_addr	addr;
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
		struct in6_addr	addr6;
#endif
	};
};

struct mptcp_out_options {
#if IS_ENABLED(CONFIG_MPTCP)
	u16 suboptions;
	struct mptcp_rm_list rm_list;
	u8 join_id;
	u8 backup;
	u8 reset_reason:4,
	   reset_transient:1,
	   csum_reqd:1,
	   allow_join_id0:1,
	   drop_ts:1;
	union {
		struct {
			u64 sndr_key;
			u64 rcvr_key;
			u64 data_seq;
			u32 subflow_seq;
			u16 data_len;
			__sum16 csum;
		};
		struct {
			struct mptcp_addr_info addr;
			u64 ahmac;
		};
		struct {
			struct mptcp_ext ext_copy;
			u64 fail_seq;
		};
		struct {
			u32 nonce;
			u32 token;
			u64 thmac;
			u8 hmac[MPTCPOPT_HMAC_LEN];
		};
	};
#endif
};

#define MPTCP_SCHED_NAME_MAX	16
#define MPTCP_SCHED_MAX		128
#define MPTCP_SCHED_BUF_MAX	(MPTCP_SCHED_NAME_MAX * MPTCP_SCHED_MAX)

struct mptcp_sched_ops {
	int (*get_send)(struct mptcp_sock *msk);
	int (*get_retrans)(struct mptcp_sock *msk);

Annotation

• Immediate include surface: `linux/skbuff.h`, `linux/tcp.h`, `linux/types.h`.
• Detected declarations: `struct mptcp_info`, `struct mptcp_sock`, `struct mptcp_pm_addr_entry`, `struct seq_file`, `struct mptcp_ext`, `struct mptcp_rm_list`, `struct mptcp_addr_info`, `struct mptcp_out_options`, `struct mptcp_sched_ops`, `struct mptcp_pm_ops`.
• Atlas domain: Networking Core / Sockets, Protocols, Packet Path, And Network Policy.
• Implementation status: source implementation candidate.

Implementation Notes

• This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
• Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
• Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.