libiscsi_tcp.h

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/*
 * iSCSI over TCP/IP Data-Path lib
 *
 * Copyright (C) 2008 Mike Christie
 * Copyright (C) 2008 Red Hat, Inc.  All rights reserved.
 * maintained by [email protected]
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published
 * by the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * See the file COPYING included with this distribution for more details.
 */

#ifndef LIBISCSI_TCP_H
#define LIBISCSI_TCP_H

#include <scsi/libiscsi.h>

struct iscsi_tcp_conn;
struct iscsi_segment;
struct sk_buff;
struct hash_desc;

typedef int iscsi_segment_done_fn_t(struct iscsi_tcp_conn *,
                    struct iscsi_segment *);

struct iscsi_segment {
    unsigned char       *data;
    unsigned int        size;
    unsigned int        copied;
    unsigned int        total_size;
    unsigned int        total_copied;

    struct hash_desc    *hash;
    unsigned char       padbuf[ISCSI_PAD_LEN];
    unsigned char       recv_digest[ISCSI_DIGEST_SIZE];
    unsigned char       digest[ISCSI_DIGEST_SIZE];
    unsigned int        digest_len;

    struct scatterlist  *sg;
    void            *sg_mapped;
    unsigned int        sg_offset;
    bool            atomic_mapped;

    iscsi_segment_done_fn_t *done;
};

/* Socket connection receive helper */
struct iscsi_tcp_recv {
    struct iscsi_hdr    *hdr;
    struct iscsi_segment    segment;

    /* Allocate buffer for BHS + AHS */
    uint32_t        hdr_buf[64];

    /* copied and flipped values */
    int         datalen;
};

struct iscsi_tcp_conn {
    struct iscsi_conn   *iscsi_conn;
    void            *dd_data;
    int         stop_stage; /* conn_stop() flag: *
                         * stop to recover,  *
                         * stop to terminate */
    /* control data */
    struct iscsi_tcp_recv   in;     /* TCP receive context */
    /* CRC32C (Rx) LLD should set this is they do not offload */
    struct hash_desc    *rx_hash;
};

struct iscsi_tcp_task {
    uint32_t        exp_datasn; /* expected target's R2TSN/DataSN */
    int         data_offset;
    struct iscsi_r2t_info   *r2t;       /* in progress solict R2T */
    struct iscsi_pool   r2tpool;
    struct kfifo        r2tqueue;
    void            *dd_data;
};

enum {
    ISCSI_TCP_SEGMENT_DONE,     /* curr seg has been processed */
    ISCSI_TCP_SKB_DONE,     /* skb is out of data */
    ISCSI_TCP_CONN_ERR,     /* iscsi layer has fired a conn err */
    ISCSI_TCP_SUSPENDED,        /* conn is suspended */
};

extern void iscsi_tcp_hdr_recv_prep(struct iscsi_tcp_conn *tcp_conn);
extern int iscsi_tcp_recv_skb(struct iscsi_conn *conn, struct sk_buff *skb,
                  unsigned int offset, bool offloaded, int *status);
extern void iscsi_tcp_cleanup_task(struct iscsi_task *task);
extern int iscsi_tcp_task_init(struct iscsi_task *task);
extern int iscsi_tcp_task_xmit(struct iscsi_task *task);

/* segment helpers */
extern int iscsi_tcp_recv_segment_is_hdr(struct iscsi_tcp_conn *tcp_conn);
extern int iscsi_tcp_segment_done(struct iscsi_tcp_conn *tcp_conn,
                  struct iscsi_segment *segment, int recv,
                  unsigned copied);
extern void iscsi_tcp_segment_unmap(struct iscsi_segment *segment);

extern void iscsi_segment_init_linear(struct iscsi_segment *segment,
                      void *data, size_t size,
                      iscsi_segment_done_fn_t *done,
                      struct hash_desc *hash);
extern int
iscsi_segment_seek_sg(struct iscsi_segment *segment,
              struct scatterlist *sg_list, unsigned int sg_count,
              unsigned int offset, size_t size,
              iscsi_segment_done_fn_t *done, struct hash_desc *hash);

/* digest helpers */
extern void iscsi_tcp_dgst_header(struct hash_desc *hash, const void *hdr,
                  size_t hdrlen,
                  unsigned char digest[ISCSI_DIGEST_SIZE]);
extern struct iscsi_cls_conn *
iscsi_tcp_conn_setup(struct iscsi_cls_session *cls_session, int dd_data_size,
             uint32_t conn_idx);
extern void iscsi_tcp_conn_teardown(struct iscsi_cls_conn *cls_conn);

/* misc helpers */
extern int iscsi_tcp_r2tpool_alloc(struct iscsi_session *session);
extern void iscsi_tcp_r2tpool_free(struct iscsi_session *session);
extern int iscsi_tcp_set_max_r2t(struct iscsi_conn *conn, char *buf);
extern void iscsi_tcp_conn_get_stats(struct iscsi_cls_conn *cls_conn,
                     struct iscsi_stats *stats);
#endif /* LIBISCSI_TCP_H */