/* 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/genetlink.h>
#include <net/sock.h>

#include "smc_ib.h"

#define SMC_V1          1               /* SMC version V1 */
#define SMC_V2          2               /* SMC version V2 */

#define SMC_RELEASE_0 0
#define SMC_RELEASE_1 1
#define SMC_RELEASE     SMC_RELEASE_1 /* the latest release version */

#define SMCPROTO_SMC            0       /* SMC protocol, IPv4 */
#define SMCPROTO_SMC6           1       /* SMC protocol, IPv6 */

#define SMC_AUTOCORKING_DEFAULT_SIZE    0x10000 /* 64K by default */

extern struct proto smc_proto;
extern struct proto smc_proto6;

extern struct smc_hashinfo smc_v4_hashinfo;
extern struct smc_hashinfo smc_v6_hashinfo;

int smc_hash_sk(struct sock *sk);
void smc_unhash_sk(struct sock *sk);
void smc_release_cb(struct sock *sk);

int smc_release(struct socket *sock);
int smc_bind(struct socket *sock, struct sockaddr_unsized *uaddr,
             int addr_len);
int smc_connect(struct socket *sock, struct sockaddr_unsized *addr,
                int alen, int flags);
int smc_accept(struct socket *sock, struct socket *new_sock,
               struct proto_accept_arg *arg);
int smc_getname(struct socket *sock, struct sockaddr *addr,
                int peer);
__poll_t smc_poll(struct file *file, struct socket *sock,
                  poll_table *wait);
int smc_ioctl(struct socket *sock, unsigned int cmd,
              unsigned long arg);
int smc_listen(struct socket *sock, int backlog);
int smc_shutdown(struct socket *sock, int how);
int smc_setsockopt(struct socket *sock, int level, int optname,
                   sockptr_t optval, unsigned int optlen);
int smc_getsockopt(struct socket *sock, int level, int optname,
                   char __user *optval, int __user *optlen);
int smc_sendmsg(struct socket *sock, struct msghdr *msg, size_t len);
int smc_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
                int flags);
ssize_t smc_splice_read(struct socket *sock, loff_t *ppos,
                        struct pipe_inode_info *pipe, size_t len,
                        unsigned int flags);

/* smc sock initialization */
void smc_sk_init(struct net *net, struct sock *sk, int protocol);
/* clcsock initialization */
int smc_create_clcsk(struct net *net, struct sock *sk, int family);

#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,
};

enum smc_supplemental_features {
        SMC_SPF_EMULATED_ISM_DEV        = 0,
};

#define SMC_FEATURE_MASK \
        (BIT(SMC_SPF_EMULATED_ISM_DEV))

struct smc_link_group;

struct smc_wr_rx_hdr {  /* common prefix part of LLC and CDC to demultiplex */
        union {
                u8 type;
#if defined(__BIG_ENDIAN_BITFIELD)
                struct {
                        u8 llc_version:4,
                           llc_type:4;
                };
#elif defined(__LITTLE_ENDIAN_BITFIELD)
                struct {
                        u8 llc_type:4,
                           llc_version:4;
                };
#endif
        };
} __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);

enum smc_urg_state {
        SMC_URG_VALID   = 1,                    /* data present */
        SMC_URG_NOTYET  = 2,                    /* data pending */
        SMC_URG_READ    = 3,                    /* data was already read */
};

struct smc_mark_woken {
        bool woken;
        void *key;
        wait_queue_entry_t wait_entry;
};

struct smc_connection {
        struct rb_node          alert_node;
        struct smc_link_group   *lgr;           /* link group of connection */
        struct smc_link         *lnk;           /* assigned SMC-R link */
        u32                     alert_token_local; /* unique conn. id */
        u8                      peer_rmbe_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 */
        struct smc_buf_desc     *rmb_desc;      /* RMBE descriptor */
        int                     rmbe_size_comp; /* 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   local_tx_ctrl_fin;
                                                /* prod crsr - confirmed by peer
                                                 */
        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 */
        u16                     tx_cdc_seq_fin; /* sequence # - tx completed */
        spinlock_t              send_lock;      /* protect wr_sends */
        atomic_t                cdc_pend_tx_wr; /* number of pending tx CDC wqe
                                                 * - inc when post wqe,
                                                 * - dec on polled tx cqe
                                                 */
        wait_queue_head_t       cdc_pend_tx_wq; /* wakeup on no cdc_pend_tx_wr*/
        struct delayed_work     tx_work;        /* retry of smc_cdc_msg_send */
        u32                     tx_off;         /* base offset in peer rmb */

        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 ?
                                                    */
        union smc_host_cursor   urg_curs;       /* points at urgent byte */
        enum smc_urg_state      urg_state;
        bool                    urg_tx_pend;    /* urgent data staged */
        bool                    urg_rx_skip_pend;
                                                /* indicate urgent oob data
                                                 * read, but previous regular
                                                 * data still pending
                                                 */
        char                    urg_rx_byte;    /* urgent byte */
        bool                    tx_in_release_sock;
                                                /* flush pending tx data in
                                                 * sock release_cb()
                                                 */
        atomic_t                bytes_to_rcv;   /* arrived data,
                                                 * not yet received
                                                 */
        atomic_t                splice_pending; /* number of spliced bytes
                                                 * pending processing
                                                 */
#ifndef KERNEL_HAS_ATOMIC64
        spinlock_t              acurs_lock;     /* protect cursors */
#endif
        struct work_struct      close_work;     /* peer sent some closing */
        struct work_struct      abort_work;     /* abort the connection */
        struct tasklet_struct   rx_tsklet;      /* Receiver tasklet for SMC-D */
        u8                      rx_off;         /* receive offset:
                                                 * 0 for SMC-R, 32 for SMC-D
                                                 */
        u64                     peer_token;     /* SMC-D token of peer */
        u8                      killed : 1;     /* abnormal termination */
        u8                      freed : 1;      /* normal termination */
        u8                      out_of_sync : 1; /* out of sync with peer */
};

struct smc_sock {                               /* smc sock container */
        union {
                struct sock             sk;
                struct inet_sock        icsk_inet;
        };
        struct socket           *clcsock;       /* internal tcp socket */
        void                    (*clcsk_state_change)(struct sock *sk);
                                                /* original stat_change fct. */
        void                    (*clcsk_data_ready)(struct sock *sk);
                                                /* original data_ready fct. */
        void                    (*clcsk_write_space)(struct sock *sk);
                                                /* original write_space fct. */
        void                    (*clcsk_error_report)(struct sock *sk);
                                                /* original error_report fct. */
        struct smc_connection   conn;           /* smc connection */
        struct smc_sock         *listen_smc;    /* listen parent */
        struct work_struct      connect_work;   /* handle non-blocking connect*/
        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 */
        bool                    limit_smc_hs;   /* put constraint on handshake */
        bool                    use_fallback;   /* fallback to tcp */
        int                     fallback_rsn;   /* reason for fallback */
        u32                     peer_diagnosis; /* decline reason from peer */
        atomic_t                queued_smc_hs;  /* queued smc handshakes */
        struct inet_connection_sock_af_ops              af_ops;
        const struct inet_connection_sock_af_ops        *ori_af_ops;
                                                /* original af ops */
        int                     sockopt_defer_accept;
                                                /* sockopt TCP_DEFER_ACCEPT
                                                 * value
                                                 */
        u8                      wait_close_tx_prepared : 1;
                                                /* shutdown wr or close
                                                 * started, waiting for unsent
                                                 * data to be sent
                                                 */
        u8                      connect_nonblock : 1;
                                                /* non-blocking connect in
                                                 * flight
                                                 */
        struct mutex            clcsock_release_lock;
                                                /* protects clcsock of a listen
                                                 * socket
                                                 * */
};

#define smc_sk(ptr) container_of_const(ptr, struct smc_sock, sk)

static inline void smc_init_saved_callbacks(struct smc_sock *smc)
{
        smc->clcsk_state_change = NULL;
        smc->clcsk_data_ready   = NULL;
        smc->clcsk_write_space  = NULL;
        smc->clcsk_error_report = NULL;
}

static inline struct smc_sock *smc_clcsock_user_data(const struct sock *clcsk)
{
        return (struct smc_sock *)
               ((uintptr_t)clcsk->sk_user_data & ~SK_USER_DATA_NOCOPY);
}

static inline struct smc_sock *smc_clcsock_user_data_rcu(const struct sock *clcsk)
{
        return (struct smc_sock *)rcu_dereference_sk_user_data(clcsk);
}

/* save target_cb in saved_cb, and replace target_cb with new_cb */
static inline void smc_clcsock_replace_cb(void (**target_cb)(struct sock *),
                                          void (*new_cb)(struct sock *),
                                          void (**saved_cb)(struct sock *))
{
        /* only save once */
        if (!*saved_cb)
                *saved_cb = *target_cb;
        *target_cb = new_cb;
}

/* restore target_cb to saved_cb, and reset saved_cb to NULL */
static inline void smc_clcsock_restore_cb(void (**target_cb)(struct sock *),
                                          void (**saved_cb)(struct sock *))
{
        if (!*saved_cb)
                return;
        *target_cb = *saved_cb;
        *saved_cb = NULL;
}

extern struct workqueue_struct  *smc_hs_wq;     /* wq for handshake work */
extern struct workqueue_struct  *smc_close_wq;  /* wq for close work */

#define SMC_SYSTEMID_LEN                8

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

#define ntohll(x) be64_to_cpu(x)
#define htonll(x) cpu_to_be64(x)

/* 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);
}

#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]) ? true : false;
}
#else
static inline bool using_ipsec(struct smc_sock *smc)
{
        return false;
}
#endif

struct smc_gidlist;

struct sock *smc_accept_dequeue(struct sock *parent, struct socket *new_sock);
void smc_close_non_accepted(struct sock *sk);
void smc_fill_gid_list(struct smc_link_group *lgr,
                       struct smc_gidlist *gidlist,
                       struct smc_ib_device *known_dev, u8 *known_gid);

/* smc handshake limitation interface for netlink  */
int smc_nl_dump_hs_limitation(struct sk_buff *skb, struct netlink_callback *cb);
int smc_nl_enable_hs_limitation(struct sk_buff *skb, struct genl_info *info);
int smc_nl_disable_hs_limitation(struct sk_buff *skb, struct genl_info *info);

static inline void smc_sock_set_flag(struct sock *sk, enum sock_flags flag)
{
        set_bit(flag, &sk->sk_flags);
}

#endif  /* __SMC_H */