path: root/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>
#include <uapi/linux/mptcp.h>
#include <net/genetlink.h>
#include <net/rstreason.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)
#define OPTION_MPTCP_MPJ_SYN	BIT(3)
#define OPTION_MPTCP_MPJ_SYNACK	BIT(4)
#define OPTION_MPTCP_MPJ_ACK	BIT(5)
#define OPTION_MPTCP_ADD_ADDR	BIT(6)
#define OPTION_MPTCP_RM_ADDR	BIT(7)
#define OPTION_MPTCP_FASTCLOSE	BIT(8)
#define OPTION_MPTCP_PRIO	BIT(9)
#define OPTION_MPTCP_RST	BIT(10)
#define OPTION_MPTCP_DSS	BIT(11)
#define OPTION_MPTCP_FAIL	BIT(12)

#define OPTION_MPTCP_CSUMREQD	BIT(13)

#define OPTIONS_MPTCP_MPC	(OPTION_MPTCP_MPC_SYN | OPTION_MPTCP_MPC_SYNACK | \
				 OPTION_MPTCP_MPC_ACK)
#define OPTIONS_MPTCP_MPJ	(OPTION_MPTCP_MPJ_SYN | OPTION_MPTCP_MPJ_SYNACK | \
				 OPTION_MPTCP_MPJ_ACK)

/* 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
#define MPTCPOPT_RST		8

/* 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_MPJ_SYN		12
#define TCPOLEN_MPTCP_MPJ_SYNACK	16
#define TCPOLEN_MPTCP_MPJ_ACK		24
#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
#define TCPOLEN_MPTCP_ADD_ADDR		16
#define TCPOLEN_MPTCP_ADD_ADDR_PORT	18
#define TCPOLEN_MPTCP_ADD_ADDR_BASE	8
#define TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT	10
#define TCPOLEN_MPTCP_ADD_ADDR6		28
#define TCPOLEN_MPTCP_ADD_ADDR6_PORT	30
#define TCPOLEN_MPTCP_ADD_ADDR6_BASE	20
#define TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT	22
#define TCPOLEN_MPTCP_PORT_LEN		2
#define TCPOLEN_MPTCP_PORT_ALIGN	2
#define TCPOLEN_MPTCP_RM_ADDR_BASE	3
#define TCPOLEN_MPTCP_PRIO		3
#define TCPOLEN_MPTCP_PRIO_ALIGN	4
#define TCPOLEN_MPTCP_FASTCLOSE		12
#define TCPOLEN_MPTCP_RST		4
#define TCPOLEN_MPTCP_FAIL		12

#define TCPOLEN_MPTCP_MPC_ACK_DATA_CSUM	(TCPOLEN_MPTCP_DSS_CHECKSUM + TCPOLEN_MPTCP_MPC_ACK_DATA)

/* MPTCP MP_JOIN flags */
#define MPTCPOPT_BACKUP		BIT(0)
#define MPTCPOPT_THMAC_LEN	8

/* 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_DENY_JOIN_ID0	BIT(5)
#define MPTCP_CAP_HMAC_SHA256	BIT(0)
#define MPTCP_CAP_FLAG_MASK	(0x1F)

/* 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 ADD_ADDR flags */
#define MPTCP_ADDR_ECHO		BIT(0)

/* MPTCP MP_PRIO flags */
#define MPTCP_PRIO_BKUP		BIT(0)

/* MPTCP TCPRST flags */
#define MPTCP_RST_TRANSIENT	BIT(0)

/* MPTCP socket atomic flags */
#define MPTCP_WORK_RTX		1
#define MPTCP_FALLBACK_DONE	2
#define MPTCP_WORK_CLOSE_SUBFLOW 3

/* MPTCP socket release cb flags */
#define MPTCP_PUSH_PENDING	1
#define MPTCP_CLEAN_UNA		2
#define MPTCP_ERROR_REPORT	3
#define MPTCP_RETRANSMIT	4
#define MPTCP_FLUSH_JOIN_LIST	5
#define MPTCP_SYNC_STATE	6
#define MPTCP_SYNC_SNDBUF	7

struct mptcp_skb_cb {
	u64 map_seq;
	u64 end_seq;
	u32 offset;
	u8  has_rxtstamp:1;
};

#define MPTCP_SKB_CB(__skb)	((struct mptcp_skb_cb *)&((__skb)->cb[0]))

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

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

struct mptcp_options_received {
	u64	sndr_key;
	u64	rcvr_key;
	u64	data_ack;
	u64	data_seq;
	u32	subflow_seq;
	u16	data_len;
	__sum16	csum;
	u16	suboptions;
	u32	token;
	u32	nonce;
	u16	use_map:1,
		dsn64:1,
		data_fin:1,
		use_ack:1,
		ack64:1,
		mpc_map:1,
		reset_reason:4,
		reset_transient:1,
		echo:1,
		backup:1,
		deny_join_id0:1,
		__unused:2;
	u8	join_id;
	u64	thmac;
	u8	hmac[MPTCPOPT_HMAC_LEN];
	struct mptcp_addr_info addr;
	struct mptcp_rm_list rm_list;
	u64	ahmac;
	u64	fail_seq;
};

static inline __be32 mptcp_option(u8 subopt, u8 len, u8 nib, u8 field)
{
	return htonl((TCPOPT_MPTCP << 24) | (len << 16) | (subopt << 12) |
		     ((nib & 0xF) << 8) | field);
}

enum mptcp_pm_status {
	MPTCP_PM_ADD_ADDR_RECEIVED,
	MPTCP_PM_ADD_ADDR_SEND_ACK,
	MPTCP_PM_RM_ADDR_RECEIVED,
	MPTCP_PM_ESTABLISHED,
	MPTCP_PM_SUBFLOW_ESTABLISHED,
	MPTCP_PM_ALREADY_ESTABLISHED,	/* persistent status, set after ESTABLISHED event */
	MPTCP_PM_MPC_ENDPOINT_ACCOUNTED /* persistent status, set after MPC local address is
					 * accounted int id_avail_bitmap
					 */