/*
* 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 */