/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __FS_CEPH_MESSENGER_H
#define __FS_CEPH_MESSENGER_H

#include <crypto/sha2.h>
#include <linux/bvec.h>
#include <linux/crypto.h>
#include <linux/kref.h>
#include <linux/mutex.h>
#include <linux/net.h>
#include <linux/radix-tree.h>
#include <linux/uio.h>
#include <linux/workqueue.h>
#include <net/net_namespace.h>

#include <linux/ceph/types.h>
#include <linux/ceph/buffer.h>

struct ceph_msg;
struct ceph_connection;
struct ceph_msg_data_cursor;

/*
 * Ceph defines these callbacks for handling connection events.
 */
struct ceph_connection_operations {
        struct ceph_connection *(*get)(struct ceph_connection *);
        void (*put)(struct ceph_connection *);

        /* handle an incoming message. */
        void (*dispatch) (struct ceph_connection *con, struct ceph_msg *m);

        /* authorize an outgoing connection */
        struct ceph_auth_handshake *(*get_authorizer) (
                                struct ceph_connection *con,
                               int *proto, int force_new);
        int (*add_authorizer_challenge)(struct ceph_connection *con,
                                        void *challenge_buf,
                                        int challenge_buf_len);
        int (*verify_authorizer_reply) (struct ceph_connection *con);
        int (*invalidate_authorizer)(struct ceph_connection *con);

        /* there was some error on the socket (disconnect, whatever) */
        void (*fault) (struct ceph_connection *con);

        /* a remote host as terminated a message exchange session, and messages
         * we sent (or they tried to send us) may be lost. */
        void (*peer_reset) (struct ceph_connection *con);

        struct ceph_msg * (*alloc_msg) (struct ceph_connection *con,
                                        struct ceph_msg_header *hdr,
                                        int *skip);

        void (*reencode_message) (struct ceph_msg *msg);

        int (*sign_message) (struct ceph_msg *msg);
        int (*check_message_signature) (struct ceph_msg *msg);

        /* msgr2 authentication exchange */
        int (*get_auth_request)(struct ceph_connection *con,
                                void *buf, int *buf_len,
                                void **authorizer, int *authorizer_len);
        int (*handle_auth_reply_more)(struct ceph_connection *con,
                                      void *reply, int reply_len,
                                      void *buf, int *buf_len,
                                      void **authorizer, int *authorizer_len);
        int (*handle_auth_done)(struct ceph_connection *con,
                                u64 global_id, void *reply, int reply_len,
                                u8 *session_key, int *session_key_len,
                                u8 *con_secret, int *con_secret_len);
        int (*handle_auth_bad_method)(struct ceph_connection *con,
                                      int used_proto, int result,
                                      const int *allowed_protos, int proto_cnt,
                                      const int *allowed_modes, int mode_cnt);

        /**
         * sparse_read: read sparse data
         * @con: connection we're reading from
         * @cursor: data cursor for reading extents
         * @buf: optional buffer to read into
         *
         * This should be called more than once, each time setting up to
         * receive an extent into the current cursor position, and zeroing
         * the holes between them.
         *
         * Returns amount of data to be read (in bytes), 0 if reading is
         * complete, or -errno if there was an error.
         *
         * If @buf is set on a >0 return, then the data should be read into
         * the provided buffer. Otherwise, it should be read into the cursor.
         *
         * The sparse read operation is expected to initialize the cursor
         * with a length covering up to the end of the last extent.
         */
        int (*sparse_read)(struct ceph_connection *con,
                           struct ceph_msg_data_cursor *cursor,
                           char **buf);

};

/* use format string %s%lld */
#define ENTITY_NAME(n) ceph_entity_type_name((n).type), le64_to_cpu((n).num)

struct ceph_messenger {
        struct ceph_entity_inst inst;    /* my name+address */
        struct ceph_entity_addr my_enc_addr;

        atomic_t stopping;
        possible_net_t net;

        /*
         * the global_seq counts connections i (attempt to) initiate
         * in order to disambiguate certain connect race conditions.
         */
        u32 global_seq;
        spinlock_t global_seq_lock;
};

enum ceph_msg_data_type {
        CEPH_MSG_DATA_NONE,     /* message contains no data payload */
        CEPH_MSG_DATA_PAGES,    /* data source/destination is a page array */
        CEPH_MSG_DATA_PAGELIST, /* data source/destination is a pagelist */
#ifdef CONFIG_BLOCK
        CEPH_MSG_DATA_BIO,      /* data source/destination is a bio list */
#endif /* CONFIG_BLOCK */
        CEPH_MSG_DATA_BVECS,    /* data source/destination is a bio_vec array */
        CEPH_MSG_DATA_ITER,     /* data source/destination is an iov_iter */
};

#ifdef CONFIG_BLOCK

struct ceph_bio_iter {
        struct bio *bio;
        struct bvec_iter iter;
};

#define __ceph_bio_iter_advance_step(it, n, STEP) do {                        \
        unsigned int __n = (n), __cur_n;                                      \
                                                                              \
        while (__n) {                                                         \
                BUG_ON(!(it)->iter.bi_size);                                  \
                __cur_n = min((it)->iter.bi_size, __n);                       \
                (void)(STEP);                                                 \
                bio_advance_iter((it)->bio, &(it)->iter, __cur_n);            \
                if (!(it)->iter.bi_size && (it)->bio->bi_next) {              \
                        dout("__ceph_bio_iter_advance_step next bio\n");      \
                        (it)->bio = (it)->bio->bi_next;                       \
                        (it)->iter = (it)->bio->bi_iter;                      \
                }                                                             \
                __n -= __cur_n;                                               \
        }                                                                     \
} while (0)

/*
 * Advance @it by @n bytes.
 */
#define ceph_bio_iter_advance(it, n)                                          \
        __ceph_bio_iter_advance_step(it, n, 0)

/*
 * Advance @it by @n bytes, executing BVEC_STEP for each bio_vec.
 */
#define ceph_bio_iter_advance_step(it, n, BVEC_STEP)                          \
        __ceph_bio_iter_advance_step(it, n, ({                                \
                struct bio_vec bv;                                            \
                struct bvec_iter __cur_iter;                                  \
                                                                              \
                __cur_iter = (it)->iter;                                      \
                __cur_iter.bi_size = __cur_n;                                 \
                __bio_for_each_segment(bv, (it)->bio, __cur_iter, __cur_iter) \
                        (void)(BVEC_STEP);                                    \
        }))

#endif /* CONFIG_BLOCK */

struct ceph_bvec_iter {
        struct bio_vec *bvecs;
        struct bvec_iter iter;
};

#define __ceph_bvec_iter_advance_step(it, n, STEP) do {                       \
        BUG_ON((n) > (it)->iter.bi_size);                                     \
        (void)(STEP);                                                         \
        bvec_iter_advance((it)->bvecs, &(it)->iter, (n));                     \
} while (0)

/*
 * Advance @it by @n bytes.
 */
#define ceph_bvec_iter_advance(it, n)                                         \
        __ceph_bvec_iter_advance_step(it, n, 0)

/*
 * Advance @it by @n bytes, executing BVEC_STEP for each bio_vec.
 */
#define ceph_bvec_iter_advance_step(it, n, BVEC_STEP)                         \
        __ceph_bvec_iter_advance_step(it, n, ({                               \
                struct bio_vec bv;                                            \
                struct bvec_iter __cur_iter;                                  \
                                                                              \
                __cur_iter = (it)->iter;                                      \
                __cur_iter.bi_size = (n);                                     \
                for_each_bvec(bv, (it)->bvecs, __cur_iter, __cur_iter)        \
                        (void)(BVEC_STEP);                                    \
        }))

#define ceph_bvec_iter_shorten(it, n) do {                                    \
        BUG_ON((n) > (it)->iter.bi_size);                                     \
        (it)->iter.bi_size = (n);                                             \
} while (0)

struct ceph_msg_data {
        enum ceph_msg_data_type         type;
        union {
#ifdef CONFIG_BLOCK
                struct {
                        struct ceph_bio_iter    bio_pos;
                        u32                     bio_length;
                };
#endif /* CONFIG_BLOCK */
                struct ceph_bvec_iter   bvec_pos;
                struct {
                        struct page     **pages;
                        size_t          length;         /* total # bytes */
                        unsigned int    alignment;      /* first page */
                        bool            own_pages;
                };
                struct ceph_pagelist    *pagelist;
                struct iov_iter         iter;
        };
};

struct ceph_msg_data_cursor {
        size_t                  total_resid;    /* across all data items */

        struct ceph_msg_data    *data;          /* current data item */
        size_t                  resid;          /* bytes not yet consumed */
        int                     sr_resid;       /* residual sparse_read len */
        bool                    need_crc;       /* crc update needed */
        union {
#ifdef CONFIG_BLOCK
                struct ceph_bio_iter    bio_iter;
#endif /* CONFIG_BLOCK */
                struct bvec_iter        bvec_iter;
                struct {                                /* pages */
                        unsigned int    page_offset;    /* offset in page */
                        unsigned short  page_index;     /* index in array */
                        unsigned short  page_count;     /* pages in array */
                };
                struct {                                /* pagelist */
                        struct page     *page;          /* page from list */
                        size_t          offset;         /* bytes from list */
                };
                struct {
                        struct iov_iter         iov_iter;
                        unsigned int            lastlen;
                };
        };
};

/*
 * a single message.  it contains a header (src, dest, message type, etc.),
 * footer (crc values, mainly), a "front" message body, and possibly a
 * data payload (stored in some number of pages).
 */
struct ceph_msg {
        struct ceph_msg_header hdr;     /* header */
        union {
                struct ceph_msg_footer footer;          /* footer */
                struct ceph_msg_footer_old old_footer;  /* old format footer */
        };
        struct kvec front;              /* unaligned blobs of message */
        struct ceph_buffer *middle;

        size_t                          data_length;
        struct ceph_msg_data            *data;
        int                             num_data_items;
        int                             max_data_items;
        struct ceph_msg_data_cursor     cursor;

        struct ceph_connection *con;
        struct list_head list_head;     /* links for connection lists */

        struct kref kref;
        bool more_to_follow;
        bool needs_out_seq;
        u64 sparse_read_total;
        int front_alloc_len;

        struct ceph_msgpool *pool;
};

/*
 * connection states
 */
#define CEPH_CON_S_CLOSED               1
#define CEPH_CON_S_PREOPEN              2
#define CEPH_CON_S_V1_BANNER            3
#define CEPH_CON_S_V1_CONNECT_MSG       4
#define CEPH_CON_S_V2_BANNER_PREFIX     5
#define CEPH_CON_S_V2_BANNER_PAYLOAD    6
#define CEPH_CON_S_V2_HELLO             7
#define CEPH_CON_S_V2_AUTH              8
#define CEPH_CON_S_V2_AUTH_SIGNATURE    9
#define CEPH_CON_S_V2_SESSION_CONNECT   10
#define CEPH_CON_S_V2_SESSION_RECONNECT 11
#define CEPH_CON_S_OPEN                 12
#define CEPH_CON_S_STANDBY              13

/*
 * ceph_connection flag bits
 */
#define CEPH_CON_F_LOSSYTX              0  /* we can close channel or drop
                                              messages on errors */
#define CEPH_CON_F_KEEPALIVE_PENDING    1  /* we need to send a keepalive */
#define CEPH_CON_F_WRITE_PENDING        2  /* we have data ready to send */
#define CEPH_CON_F_SOCK_CLOSED          3  /* socket state changed to closed */
#define CEPH_CON_F_BACKOFF              4  /* need to retry queuing delayed
                                              work */

/* ceph connection fault delay defaults, for exponential backoff */
#define BASE_DELAY_INTERVAL     (HZ / 4)
#define MAX_DELAY_INTERVAL      (15 * HZ)

struct ceph_connection_v1_info {
        struct kvec out_kvec[8],         /* sending header/footer data */
                *out_kvec_cur;
        int out_kvec_left;   /* kvec's left in out_kvec */
        int out_skip;        /* skip this many bytes */
        int out_kvec_bytes;  /* total bytes left */
        bool out_more;       /* there is more data after the kvecs */
        bool out_msg_done;

        struct ceph_auth_handshake *auth;
        int auth_retry;       /* true if we need a newer authorizer */

        /* connection negotiation temps */
        u8 in_banner[CEPH_BANNER_MAX_LEN];
        struct ceph_entity_addr actual_peer_addr;
        struct ceph_entity_addr peer_addr_for_me;
        struct ceph_msg_connect out_connect;
        struct ceph_msg_connect_reply in_reply;

        int in_base_pos;     /* bytes read */

        /* sparse reads */
        struct kvec in_sr_kvec; /* current location to receive into */
        u64 in_sr_len;          /* amount of data in this extent */

        /* message in temps */
        u8 in_tag;           /* protocol control byte */
        struct ceph_msg_header in_hdr;
        __le64 in_temp_ack;  /* for reading an ack */

        /* message out temps */
        struct ceph_msg_header out_hdr;
        __le64 out_temp_ack;  /* for writing an ack */
        struct ceph_timespec out_temp_keepalive2;  /* for writing keepalive2
                                                      stamp */

        u32 connect_seq;      /* identify the most recent connection
                                 attempt for this session */
        u32 peer_global_seq;  /* peer's global seq for this connection */
};

#define CEPH_CRC_LEN                    4
#define CEPH_GCM_KEY_LEN                16
#define CEPH_GCM_IV_LEN                 sizeof(struct ceph_gcm_nonce)
#define CEPH_GCM_BLOCK_LEN              16
#define CEPH_GCM_TAG_LEN                16

#define CEPH_PREAMBLE_LEN               32
#define CEPH_PREAMBLE_INLINE_LEN        48
#define CEPH_PREAMBLE_PLAIN_LEN         CEPH_PREAMBLE_LEN
#define CEPH_PREAMBLE_SECURE_LEN        (CEPH_PREAMBLE_LEN +            \
                                         CEPH_PREAMBLE_INLINE_LEN +     \
                                         CEPH_GCM_TAG_LEN)
#define CEPH_EPILOGUE_PLAIN_LEN         (1 + 3 * CEPH_CRC_LEN)
#define CEPH_EPILOGUE_SECURE_LEN        (CEPH_GCM_BLOCK_LEN + CEPH_GCM_TAG_LEN)

#define CEPH_FRAME_MAX_SEGMENT_COUNT    4

struct ceph_frame_desc {
        int fd_tag;  /* FRAME_TAG_* */
        int fd_seg_cnt;
        int fd_lens[CEPH_FRAME_MAX_SEGMENT_COUNT];  /* logical */
        int fd_aligns[CEPH_FRAME_MAX_SEGMENT_COUNT];
};

struct ceph_gcm_nonce {
        __le32 fixed;
        __le64 counter __packed;
};

struct ceph_connection_v2_info {
        struct iov_iter in_iter;
        struct kvec in_kvecs[5];  /* recvmsg */
        struct bio_vec in_bvec;  /* recvmsg (in_cursor) */
        int in_kvec_cnt;
        int in_state;  /* IN_S_* */

        struct iov_iter out_iter;
        struct kvec out_kvecs[8];  /* sendmsg */
        struct bio_vec out_bvec;  /* sendpage (out_cursor, out_zero),
                                     sendmsg (out_enc_pages) */
        int out_kvec_cnt;
        int out_state;  /* OUT_S_* */

        int out_zero;  /* # of zero bytes to send */
        bool out_iter_sendpage;  /* use sendpage if possible */

        struct ceph_frame_desc in_desc;
        struct ceph_msg_data_cursor in_cursor;
        struct ceph_msg_data_cursor out_cursor;

        struct hmac_sha256_key hmac_key;  /* post-auth signature */
        bool hmac_key_set;
        struct crypto_aead *gcm_tfm;  /* on-wire encryption */
        struct aead_request *gcm_req;
        struct crypto_wait gcm_wait;
        struct ceph_gcm_nonce in_gcm_nonce;
        struct ceph_gcm_nonce out_gcm_nonce;

        struct page **in_enc_pages;
        int in_enc_page_cnt;
        int in_enc_resid;
        int in_enc_i;
        struct page **out_enc_pages;
        int out_enc_page_cnt;
        int out_enc_resid;
        int out_enc_i;

        int con_mode;  /* CEPH_CON_MODE_* */

        void *conn_bufs[16];
        int conn_buf_cnt;
        int data_len_remain;

        struct kvec in_sign_kvecs[8];
        struct kvec out_sign_kvecs[8];
        int in_sign_kvec_cnt;
        int out_sign_kvec_cnt;

        u64 client_cookie;
        u64 server_cookie;
        u64 global_seq;
        u64 connect_seq;
        u64 peer_global_seq;

        u8 in_buf[CEPH_PREAMBLE_SECURE_LEN];
        u8 out_buf[CEPH_PREAMBLE_SECURE_LEN];
        struct {
                u8 late_status;  /* FRAME_LATE_STATUS_* */
                union {
                        struct {
                                u32 front_crc;
                                u32 middle_crc;
                                u32 data_crc;
                        } __packed;
                        u8 pad[CEPH_GCM_BLOCK_LEN - 1];
                };
        } out_epil;
};

/*
 * A single connection with another host.
 *
 * We maintain a queue of outgoing messages, and some session state to
 * ensure that we can preserve the lossless, ordered delivery of
 * messages in the case of a TCP disconnect.
 */
struct ceph_connection {
        void *private;

        const struct ceph_connection_operations *ops;

        struct ceph_messenger *msgr;

        int state;  /* CEPH_CON_S_* */
        atomic_t sock_state;
        struct socket *sock;

        unsigned long flags;  /* CEPH_CON_F_* */
        const char *error_msg;  /* error message, if any */

        struct ceph_entity_name peer_name; /* peer name */
        struct ceph_entity_addr peer_addr; /* peer address */
        u64 peer_features;

        struct mutex mutex;

        /* out queue */
        struct list_head out_queue;
        struct list_head out_sent;   /* sending or sent but unacked */
        u64 out_seq;                 /* last message queued for send */

        u64 in_seq, in_seq_acked;  /* last message received, acked */

        struct ceph_msg *in_msg;
        struct ceph_msg *out_msg;        /* sending message (== tail of
                                            out_sent) */

        struct page *bounce_page;
        u32 in_front_crc, in_middle_crc, in_data_crc;  /* calculated crc */

        struct timespec64 last_keepalive_ack; /* keepalive2 ack stamp */

        struct delayed_work work;           /* send|recv work */
        unsigned long       delay;          /* current delay interval */

        union {
                struct ceph_connection_v1_info v1;
                struct ceph_connection_v2_info v2;
        };
};

extern struct page *ceph_zero_page;

void ceph_con_flag_clear(struct ceph_connection *con, unsigned long con_flag);
void ceph_con_flag_set(struct ceph_connection *con, unsigned long con_flag);
bool ceph_con_flag_test(struct ceph_connection *con, unsigned long con_flag);
bool ceph_con_flag_test_and_clear(struct ceph_connection *con,
                                  unsigned long con_flag);
bool ceph_con_flag_test_and_set(struct ceph_connection *con,
                                unsigned long con_flag);

void ceph_encode_my_addr(struct ceph_messenger *msgr);

int ceph_tcp_connect(struct ceph_connection *con);
int ceph_con_close_socket(struct ceph_connection *con);
void ceph_con_reset_session(struct ceph_connection *con);

u32 ceph_get_global_seq(struct ceph_messenger *msgr, u32 gt);
void ceph_con_discard_sent(struct ceph_connection *con, u64 ack_seq);
void ceph_con_discard_requeued(struct ceph_connection *con, u64 reconnect_seq);

void ceph_msg_data_cursor_init(struct ceph_msg_data_cursor *cursor,
                               struct ceph_msg *msg, size_t length);
struct page *ceph_msg_data_next(struct ceph_msg_data_cursor *cursor,
                                size_t *page_offset, size_t *length);
void ceph_msg_data_advance(struct ceph_msg_data_cursor *cursor, size_t bytes);

u32 ceph_crc32c_page(u32 crc, struct page *page, unsigned int page_offset,
                     unsigned int length);

bool ceph_addr_is_blank(const struct ceph_entity_addr *addr);
int ceph_addr_port(const struct ceph_entity_addr *addr);
void ceph_addr_set_port(struct ceph_entity_addr *addr, int p);

void ceph_con_process_message(struct ceph_connection *con);
int ceph_con_in_msg_alloc(struct ceph_connection *con,
                          struct ceph_msg_header *hdr, int *skip);
struct ceph_msg *ceph_con_get_out_msg(struct ceph_connection *con);

/* messenger_v1.c */
int ceph_con_v1_try_read(struct ceph_connection *con);
int ceph_con_v1_try_write(struct ceph_connection *con);
void ceph_con_v1_revoke(struct ceph_connection *con, struct ceph_msg *msg);
void ceph_con_v1_revoke_incoming(struct ceph_connection *con);
bool ceph_con_v1_opened(struct ceph_connection *con);
void ceph_con_v1_reset_session(struct ceph_connection *con);
void ceph_con_v1_reset_protocol(struct ceph_connection *con);

/* messenger_v2.c */
int ceph_con_v2_try_read(struct ceph_connection *con);
int ceph_con_v2_try_write(struct ceph_connection *con);
void ceph_con_v2_revoke(struct ceph_connection *con, struct ceph_msg *msg);
void ceph_con_v2_revoke_incoming(struct ceph_connection *con);
bool ceph_con_v2_opened(struct ceph_connection *con);
void ceph_con_v2_reset_session(struct ceph_connection *con);
void ceph_con_v2_reset_protocol(struct ceph_connection *con);


extern const char *ceph_pr_addr(const struct ceph_entity_addr *addr);

extern int ceph_parse_ips(const char *c, const char *end,
                          struct ceph_entity_addr *addr,
                          int max_count, int *count, char delim);

extern int ceph_msgr_init(void);
extern void ceph_msgr_exit(void);
extern void ceph_msgr_flush(void);

extern void ceph_messenger_init(struct ceph_messenger *msgr,
                                struct ceph_entity_addr *myaddr);
extern void ceph_messenger_fini(struct ceph_messenger *msgr);
extern void ceph_messenger_reset_nonce(struct ceph_messenger *msgr);

extern void ceph_con_init(struct ceph_connection *con, void *private,
                        const struct ceph_connection_operations *ops,
                        struct ceph_messenger *msgr);
extern void ceph_con_open(struct ceph_connection *con,
                          __u8 entity_type, __u64 entity_num,
                          struct ceph_entity_addr *addr);
extern bool ceph_con_opened(struct ceph_connection *con);
extern void ceph_con_close(struct ceph_connection *con);
extern void ceph_con_send(struct ceph_connection *con, struct ceph_msg *msg);

extern void ceph_msg_revoke(struct ceph_msg *msg);
extern void ceph_msg_revoke_incoming(struct ceph_msg *msg);

extern void ceph_con_keepalive(struct ceph_connection *con);
extern bool ceph_con_keepalive_expired(struct ceph_connection *con,
                                       unsigned long interval);

void ceph_msg_data_add_pages(struct ceph_msg *msg, struct page **pages,
                             size_t length, size_t alignment, bool own_pages);
extern void ceph_msg_data_add_pagelist(struct ceph_msg *msg,
                                struct ceph_pagelist *pagelist);
#ifdef CONFIG_BLOCK
void ceph_msg_data_add_bio(struct ceph_msg *msg, struct ceph_bio_iter *bio_pos,
                           u32 length);
#endif /* CONFIG_BLOCK */
void ceph_msg_data_add_bvecs(struct ceph_msg *msg,
                             struct ceph_bvec_iter *bvec_pos);
void ceph_msg_data_add_iter(struct ceph_msg *msg,
                            struct iov_iter *iter);

struct ceph_msg *ceph_msg_new2(int type, int front_len, int max_data_items,
                               gfp_t flags, bool can_fail);
extern struct ceph_msg *ceph_msg_new(int type, int front_len, gfp_t flags,
                                     bool can_fail);

extern struct ceph_msg *ceph_msg_get(struct ceph_msg *msg);
extern void ceph_msg_put(struct ceph_msg *msg);

extern void ceph_msg_dump(struct ceph_msg *msg);

#endif