root/include/scsi/libiscsi_tcp.h

/*
 * iSCSI over TCP/IP Data-Path lib
 *
 * Copyright (C) 2008 Mike Christie
 * Copyright (C) 2008 Red Hat, Inc.  All rights reserved.
 * maintained by open-iscsi@googlegroups.com
 *
 * 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;
        spinlock_t              pool2queue;
        spinlock_t              queue2pool;
};

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 */