/* SPDX-License-Identifier: GPL-2.0 */

  /*
   *  Shared Memory Communications over RDMA (SMC-R) and RoCE
   *
   *  Definitions for the SMC module (socket related)
   *
   *  Copyright IBM Corp. 2016
   *
   *  Author(s):  Ursula Braun <ubraun@linux.vnet.ibm.com>
   */
  #ifndef __SMC_H
  #define __SMC_H
  
  #include <linux/socket.h>
  #include <linux/types.h>

  #include <linux/compiler.h> /* __aligned */

  #include <net/sock.h>

  #include "smc_ib.h"

  #define SMCPROTO_SMC		0	/* SMC protocol */

  #define SMC_MAX_PORTS		2	/* Max # of ports */

  extern struct proto smc_proto;

  #ifdef ATOMIC64_INIT
  #define KERNEL_HAS_ATOMIC64
  #endif

  enum smc_state {		/* possible states of an SMC socket */
  	SMC_ACTIVE	= 1,
  	SMC_INIT	= 2,
  	SMC_CLOSED	= 7,
  	SMC_LISTEN	= 10,

  	/* normal close */
  	SMC_PEERCLOSEWAIT1	= 20,
  	SMC_PEERCLOSEWAIT2	= 21,
  	SMC_APPFINCLOSEWAIT	= 24,
  	SMC_APPCLOSEWAIT1	= 22,
  	SMC_APPCLOSEWAIT2	= 23,
  	SMC_PEERFINCLOSEWAIT	= 25,
  	/* abnormal close */
  	SMC_PEERABORTWAIT	= 26,
  	SMC_PROCESSABORT	= 27,

  };

  struct smc_link_group;

  struct smc_wr_rx_hdr {	/* common prefix part of LLC and CDC to demultiplex */
  	u8			type;
  } __aligned(1);

  struct smc_cdc_conn_state_flags {
  #if defined(__BIG_ENDIAN_BITFIELD)
  	u8	peer_done_writing : 1;	/* Sending done indicator */
  	u8	peer_conn_closed : 1;	/* Peer connection closed indicator */
  	u8	peer_conn_abort : 1;	/* Abnormal close indicator */
  	u8	reserved : 5;
  #elif defined(__LITTLE_ENDIAN_BITFIELD)
  	u8	reserved : 5;
  	u8	peer_conn_abort : 1;
  	u8	peer_conn_closed : 1;
  	u8	peer_done_writing : 1;
  #endif
  };
  
  struct smc_cdc_producer_flags {
  #if defined(__BIG_ENDIAN_BITFIELD)
  	u8	write_blocked : 1;	/* Writing Blocked, no rx buf space */
  	u8	urg_data_pending : 1;	/* Urgent Data Pending */
  	u8	urg_data_present : 1;	/* Urgent Data Present */
  	u8	cons_curs_upd_req : 1;	/* cursor update requested */
  	u8	failover_validation : 1;/* message replay due to failover */
  	u8	reserved : 3;
  #elif defined(__LITTLE_ENDIAN_BITFIELD)
  	u8	reserved : 3;
  	u8	failover_validation : 1;
  	u8	cons_curs_upd_req : 1;
  	u8	urg_data_present : 1;
  	u8	urg_data_pending : 1;
  	u8	write_blocked : 1;
  #endif
  };
  
  /* in host byte order */
  union smc_host_cursor {	/* SMC cursor - an offset in an RMBE */
  	struct {
  		u16	reserved;
  		u16	wrap;		/* window wrap sequence number */
  		u32	count;		/* cursor (= offset) part */
  	};
  #ifdef KERNEL_HAS_ATOMIC64
  	atomic64_t		acurs;	/* for atomic processing */
  #else
  	u64			acurs;	/* for atomic processing */
  #endif
  } __aligned(8);
  
  /* in host byte order, except for flag bitfields in network byte order */
  struct smc_host_cdc_msg {		/* Connection Data Control message */
  	struct smc_wr_rx_hdr		common; /* .type = 0xFE */
  	u8				len;	/* length = 44 */
  	u16				seqno;	/* connection seq # */
  	u32				token;	/* alert_token */
  	union smc_host_cursor		prod;		/* producer cursor */
  	union smc_host_cursor		cons;		/* consumer cursor,
  							 * piggy backed "ack"
  							 */
  	struct smc_cdc_producer_flags	prod_flags;	/* conn. tx/rx status */
  	struct smc_cdc_conn_state_flags	conn_state_flags; /* peer conn. status*/
  	u8				reserved[18];
  } __aligned(8);

  struct smc_connection {
  	struct rb_node		alert_node;
  	struct smc_link_group	*lgr;		/* link group of connection */
  	u32			alert_token_local; /* unique conn. id */
  	u8			peer_conn_idx;	/* from tcp handshake */

  	int			peer_rmbe_size;	/* size of peer rx buffer */
  	atomic_t		peer_rmbe_space;/* remaining free bytes in peer
  						 * rmbe
  						 */

  	int			rtoken_idx;	/* idx to peer RMB rkey/addr */

  
  	struct smc_buf_desc	*sndbuf_desc;	/* send buffer descriptor */
  	int			sndbuf_size;	/* sndbuf size <== sock wmem */
  	struct smc_buf_desc	*rmb_desc;	/* RMBE descriptor */
  	int			rmbe_size;	/* RMBE size <== sock rmem */
  	int			rmbe_size_short;/* compressed notation */

  	int			rmbe_update_limit;
  						/* lower limit for consumer
  						 * cursor update
  						 */

  
  	struct smc_host_cdc_msg	local_tx_ctrl;	/* host byte order staging
  						 * buffer for CDC msg send
  						 * .prod cf. TCP snd_nxt
  						 * .cons cf. TCP sends ack
  						 */
  	union smc_host_cursor	tx_curs_prep;	/* tx - prepared data
  						 * snd_max..wmem_alloc
  						 */
  	union smc_host_cursor	tx_curs_sent;	/* tx - sent data
  						 * snd_nxt ?
  						 */
  	union smc_host_cursor	tx_curs_fin;	/* tx - confirmed by peer
  						 * snd-wnd-begin ?
  						 */
  	atomic_t		sndbuf_space;	/* remaining space in sndbuf */
  	u16			tx_cdc_seq;	/* sequence # for CDC send */
  	spinlock_t		send_lock;	/* protect wr_sends */

  	struct delayed_work	tx_work;	/* retry of smc_cdc_msg_send */

  
  	struct smc_host_cdc_msg	local_rx_ctrl;	/* filled during event_handl.
  						 * .prod cf. TCP rcv_nxt
  						 * .cons cf. TCP snd_una
  						 */
  	union smc_host_cursor	rx_curs_confirmed; /* confirmed to peer
  						    * source of snd_una ?
  						    */
  	atomic_t		bytes_to_rcv;	/* arrived data,
  						 * not yet received
  						 */
  #ifndef KERNEL_HAS_ATOMIC64
  	spinlock_t		acurs_lock;	/* protect cursors */
  #endif

  	struct work_struct	close_work;	/* peer sent some closing */

  };

  struct smc_sock {				/* smc sock container */
  	struct sock		sk;
  	struct socket		*clcsock;	/* internal tcp socket */

  	struct smc_connection	conn;		/* smc connection */

  	struct sockaddr		*addr;		/* inet connect address */
  	struct smc_sock		*listen_smc;	/* listen parent */
  	struct work_struct	tcp_listen_work;/* handle tcp socket accepts */
  	struct work_struct	smc_listen_work;/* prepare new accept socket */
  	struct list_head	accept_q;	/* sockets to be accepted */
  	spinlock_t		accept_q_lock;	/* protects accept_q */

  	struct delayed_work	sock_put_work;	/* final socket freeing */

  	bool			use_fallback;	/* fallback to tcp */

  	u8			wait_close_tx_prepared : 1;
  						/* shutdown wr or close
  						 * started, waiting for unsent
  						 * data to be sent
  						 */

  };
  
  static inline struct smc_sock *smc_sk(const struct sock *sk)
  {
  	return (struct smc_sock *)sk;
  }

  #define SMC_SYSTEMID_LEN		8
  
  extern u8	local_systemid[SMC_SYSTEMID_LEN]; /* unique system identifier */

  /* convert an u32 value into network byte order, store it into a 3 byte field */
  static inline void hton24(u8 *net, u32 host)
  {
  	__be32 t;
  
  	t = cpu_to_be32(host);
  	memcpy(net, ((u8 *)&t) + 1, 3);
  }
  
  /* convert a received 3 byte field into host byte order*/
  static inline u32 ntoh24(u8 *net)
  {
  	__be32 t = 0;
  
  	memcpy(((u8 *)&t) + 1, net, 3);
  	return be32_to_cpu(t);
  }

  #define SMC_BUF_MIN_SIZE 16384		/* minimum size of an RMB */
  
  #define SMC_RMBE_SIZES	16	/* number of distinct sizes for an RMBE */
  /* theoretically, the RFC states that largest size would be 512K,
   * i.e. compressed 5 and thus 6 sizes (0..5), despite
   * struct smc_clc_msg_accept_confirm.rmbe_size being a 4 bit value (0..15)
   */
  
  /* convert the RMB size into the compressed notation - minimum 16K.
   * In contrast to plain ilog2, this rounds towards the next power of 2,
   * so the socket application gets at least its desired sndbuf / rcvbuf size.
   */
  static inline u8 smc_compress_bufsize(int size)
  {
  	u8 compressed;
  
  	if (size <= SMC_BUF_MIN_SIZE)
  		return 0;
  
  	size = (size - 1) >> 14;
  	compressed = ilog2(size) + 1;
  	if (compressed >= SMC_RMBE_SIZES)
  		compressed = SMC_RMBE_SIZES - 1;
  	return compressed;
  }
  
  /* convert the RMB size from compressed notation into integer */
  static inline int smc_uncompress_bufsize(u8 compressed)
  {
  	u32 size;
  
  	size = 0x00000001 << (((int)compressed) + 14);
  	return (int)size;
  }

  #ifdef CONFIG_XFRM
  static inline bool using_ipsec(struct smc_sock *smc)
  {
  	return (smc->clcsock->sk->sk_policy[0] ||
  		smc->clcsock->sk->sk_policy[1]) ? 1 : 0;
  }
  #else
  static inline bool using_ipsec(struct smc_sock *smc)
  {
  	return 0;
  }
  #endif

  struct smc_clc_msg_local;

  int smc_netinfo_by_tcpsk(struct socket *clcsock, __be32 *subnet,
  			 u8 *prefix_len);

  void smc_conn_free(struct smc_connection *conn);
  int smc_conn_create(struct smc_sock *smc, __be32 peer_in_addr,
  		    struct smc_ib_device *smcibdev, u8 ibport,
  		    struct smc_clc_msg_local *lcl, int srv_first_contact);

  struct sock *smc_accept_dequeue(struct sock *parent, struct socket *new_sock);
  void smc_close_non_accepted(struct sock *sk);

  #endif	/* __SMC_H */