messenger.h

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#ifndef __FS_CEPH_MESSENGER_H
#define __FS_CEPH_MESSENGER_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 <linux/ceph/types.h>
#include <linux/ceph/buffer.h>

struct ceph_msg;
struct ceph_connection;

/*
 * 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 (*verify_authorizer_reply) (struct ceph_connection *con, int len);
    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);
};

/* use format string %s%d */
#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;
    bool nocrc;

    /*
     * 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;

    u32 supported_features;
    u32 required_features;
};

/*
 * 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 */
    struct ceph_msg_footer footer;  /* footer */
    struct kvec front;              /* unaligned blobs of message */
    struct ceph_buffer *middle;
    struct page **pages;            /* data payload.  NOT OWNER. */
    unsigned nr_pages;              /* size of page array */
    unsigned page_alignment;        /* io offset in first page */
    struct ceph_pagelist *pagelist; /* instead of pages */

    struct ceph_connection *con;
    struct list_head list_head;

    struct kref kref;
    struct bio  *bio;       /* instead of pages/pagelist */
    struct bio  *bio_iter;      /* bio iterator */
    int bio_seg;            /* current bio segment */
    struct ceph_pagelist *trail;    /* the trailing part of the data */
    bool front_is_vmalloc;
    bool more_to_follow;
    bool needs_out_seq;
    int front_max;
    unsigned long ack_stamp;        /* tx: when we were acked */

    struct ceph_msgpool *pool;
};

struct ceph_msg_pos {
    int page, page_pos;  /* which page; offset in page */
    int data_pos;        /* offset in data payload */
    bool did_page_crc;   /* true if we've calculated crc for current page */
};

/* ceph connection fault delay defaults, for exponential backoff */
#define BASE_DELAY_INTERVAL (HZ/2)
#define MAX_DELAY_INTERVAL  (5 * 60 * HZ)

/*
 * 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;

    atomic_t sock_state;
    struct socket *sock;
    struct ceph_entity_addr peer_addr; /* peer address */
    struct ceph_entity_addr peer_addr_for_me;

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

    struct ceph_entity_name peer_name; /* peer name */

    unsigned peer_features;
    u32 connect_seq;      /* identify the most recent connection
                 attempt for this connection, client */
    u32 peer_global_seq;  /* peer's global seq for this connection */

    int auth_retry;       /* true if we need a newer authorizer */
    void *auth_reply_buf;   /* where to put the authorizer reply */
    int auth_reply_buf_len;

    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 */

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

    /* message out temps */
    struct ceph_msg *out_msg;        /* sending message (== tail of
                        out_sent) */
    bool out_msg_done;
    struct ceph_msg_pos out_msg_pos;

    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_kvec_is_msg; /* kvec refers to out_msg */
    int out_more;        /* there is more data after the kvecs */
    __le64 out_temp_ack; /* for writing an ack */

    /* message in temps */
    struct ceph_msg_header in_hdr;
    struct ceph_msg *in_msg;
    struct ceph_msg_pos in_msg_pos;
    u32 in_front_crc, in_middle_crc, in_data_crc;  /* calculated crc */

    char in_tag;         /* protocol control byte */
    int in_base_pos;     /* bytes read */
    __le64 in_temp_ack;  /* for reading an ack */

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


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


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,
            u32 supported_features,
            u32 required_features,
            bool nocrc);

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 struct ceph_msg *ceph_msg_new(int type, int front_len, gfp_t flags,
                     bool can_fail);
extern void ceph_msg_kfree(struct ceph_msg *m);


static inline struct ceph_msg *ceph_msg_get(struct ceph_msg *msg)
{
    kref_get(&msg->kref);
    return msg;
}
extern void ceph_msg_last_put(struct kref *kref);
static inline void ceph_msg_put(struct ceph_msg *msg)
{
    kref_put(&msg->kref, ceph_msg_last_put);
}

extern void ceph_msg_dump(struct ceph_msg *msg);

#endif