1/*
2 * iSCSI over TCP/IP Data-Path lib
3 *
4 * Copyright (C) 2008 Mike Christie
5 * Copyright (C) 2008 Red Hat, Inc.  All rights reserved.
6 * maintained by open-iscsi@googlegroups.com
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published
10 * by the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful, but
14 * WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * General Public License for more details.
17 *
18 * See the file COPYING included with this distribution for more details.
19 */
20
21#ifndef LIBISCSI_TCP_H
22#define LIBISCSI_TCP_H
23
24#include <scsi/libiscsi.h>
25
26struct iscsi_tcp_conn;
27struct iscsi_segment;
28struct sk_buff;
29struct hash_desc;
30
31typedef int iscsi_segment_done_fn_t(struct iscsi_tcp_conn *,
32				    struct iscsi_segment *);
33
34struct iscsi_segment {
35	unsigned char		*data;
36	unsigned int		size;
37	unsigned int		copied;
38	unsigned int		total_size;
39	unsigned int		total_copied;
40
41	struct hash_desc	*hash;
42	unsigned char		padbuf[ISCSI_PAD_LEN];
43	unsigned char		recv_digest[ISCSI_DIGEST_SIZE];
44	unsigned char		digest[ISCSI_DIGEST_SIZE];
45	unsigned int		digest_len;
46
47	struct scatterlist	*sg;
48	void			*sg_mapped;
49	unsigned int		sg_offset;
50	bool			atomic_mapped;
51
52	iscsi_segment_done_fn_t	*done;
53};
54
55/* Socket connection receive helper */
56struct iscsi_tcp_recv {
57	struct iscsi_hdr	*hdr;
58	struct iscsi_segment	segment;
59
60	/* Allocate buffer for BHS + AHS */
61	uint32_t		hdr_buf[64];
62
63	/* copied and flipped values */
64	int			datalen;
65};
66
67struct iscsi_tcp_conn {
68	struct iscsi_conn	*iscsi_conn;
69	void			*dd_data;
70	int			stop_stage;	/* conn_stop() flag: *
71						 * stop to recover,  *
72						 * stop to terminate */
73	/* control data */
74	struct iscsi_tcp_recv	in;		/* TCP receive context */
75	/* CRC32C (Rx) LLD should set this is they do not offload */
76	struct hash_desc	*rx_hash;
77};
78
79struct iscsi_tcp_task {
80	uint32_t		exp_datasn;	/* expected target's R2TSN/DataSN */
81	int			data_offset;
82	struct iscsi_r2t_info	*r2t;		/* in progress solict R2T */
83	struct iscsi_pool	r2tpool;
84	struct kfifo		r2tqueue;
85	void			*dd_data;
86	spinlock_t		pool2queue;
87	spinlock_t		queue2pool;
88};
89
90enum {
91	ISCSI_TCP_SEGMENT_DONE,		/* curr seg has been processed */
92	ISCSI_TCP_SKB_DONE,		/* skb is out of data */
93	ISCSI_TCP_CONN_ERR,		/* iscsi layer has fired a conn err */
94	ISCSI_TCP_SUSPENDED,		/* conn is suspended */
95};
96
97extern void iscsi_tcp_hdr_recv_prep(struct iscsi_tcp_conn *tcp_conn);
98extern int iscsi_tcp_recv_skb(struct iscsi_conn *conn, struct sk_buff *skb,
99			      unsigned int offset, bool offloaded, int *status);
100extern void iscsi_tcp_cleanup_task(struct iscsi_task *task);
101extern int iscsi_tcp_task_init(struct iscsi_task *task);
102extern int iscsi_tcp_task_xmit(struct iscsi_task *task);
103
104/* segment helpers */
105extern int iscsi_tcp_recv_segment_is_hdr(struct iscsi_tcp_conn *tcp_conn);
106extern int iscsi_tcp_segment_done(struct iscsi_tcp_conn *tcp_conn,
107				  struct iscsi_segment *segment, int recv,
108				  unsigned copied);
109extern void iscsi_tcp_segment_unmap(struct iscsi_segment *segment);
110
111extern void iscsi_segment_init_linear(struct iscsi_segment *segment,
112				      void *data, size_t size,
113				      iscsi_segment_done_fn_t *done,
114				      struct hash_desc *hash);
115extern int
116iscsi_segment_seek_sg(struct iscsi_segment *segment,
117		      struct scatterlist *sg_list, unsigned int sg_count,
118		      unsigned int offset, size_t size,
119		      iscsi_segment_done_fn_t *done, struct hash_desc *hash);
120
121/* digest helpers */
122extern void iscsi_tcp_dgst_header(struct hash_desc *hash, const void *hdr,
123				  size_t hdrlen,
124				  unsigned char digest[ISCSI_DIGEST_SIZE]);
125extern struct iscsi_cls_conn *
126iscsi_tcp_conn_setup(struct iscsi_cls_session *cls_session, int dd_data_size,
127		     uint32_t conn_idx);
128extern void iscsi_tcp_conn_teardown(struct iscsi_cls_conn *cls_conn);
129
130/* misc helpers */
131extern int iscsi_tcp_r2tpool_alloc(struct iscsi_session *session);
132extern void iscsi_tcp_r2tpool_free(struct iscsi_session *session);
133extern int iscsi_tcp_set_max_r2t(struct iscsi_conn *conn, char *buf);
134extern void iscsi_tcp_conn_get_stats(struct iscsi_cls_conn *cls_conn,
135				     struct iscsi_stats *stats);
136#endif /* LIBISCSI_TCP_H */
137