xref: /linux/include/scsi/libiscsi_tcp.h (revision 2e3fcbcc3b0eb9b96d2912cdac920f0ae8d1c8f2)
1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3  * iSCSI over TCP/IP Data-Path lib
4  *
5  * Copyright (C) 2008 Mike Christie
6  * Copyright (C) 2008 Red Hat, Inc.  All rights reserved.
7  * maintained by open-iscsi@googlegroups.com
8  */
9 
10 #ifndef LIBISCSI_TCP_H
11 #define LIBISCSI_TCP_H
12 
13 #include <scsi/libiscsi.h>
14 
15 struct iscsi_tcp_conn;
16 struct iscsi_segment;
17 struct sk_buff;
18 
19 typedef int iscsi_segment_done_fn_t(struct iscsi_tcp_conn *,
20 				    struct iscsi_segment *);
21 
22 struct iscsi_segment {
23 	unsigned char		*data;
24 	unsigned int		size;
25 	unsigned int		copied;
26 	unsigned int		total_size;
27 	unsigned int		total_copied;
28 
29 	u32			*crcp;
30 	unsigned char		padbuf[ISCSI_PAD_LEN];
31 	unsigned char		recv_digest[ISCSI_DIGEST_SIZE];
32 	unsigned char		digest[ISCSI_DIGEST_SIZE];
33 	unsigned int		digest_len;
34 
35 	struct scatterlist	*sg;
36 	void			*sg_mapped;
37 	unsigned int		sg_offset;
38 	bool			atomic_mapped;
39 
40 	iscsi_segment_done_fn_t	*done;
41 };
42 
43 /* Socket connection receive helper */
44 struct iscsi_tcp_recv {
45 	struct iscsi_hdr	*hdr;
46 	struct iscsi_segment	segment;
47 
48 	/* Allocate buffer for BHS + AHS */
49 	uint32_t		hdr_buf[64];
50 
51 	/* copied and flipped values */
52 	int			datalen;
53 };
54 
55 struct iscsi_tcp_conn {
56 	struct iscsi_conn	*iscsi_conn;
57 	void			*dd_data;
58 	int			stop_stage;	/* conn_stop() flag: *
59 						 * stop to recover,  *
60 						 * stop to terminate */
61 	/* control data */
62 	struct iscsi_tcp_recv	in;		/* TCP receive context */
63 	/* CRC32C (Rx) LLD should set this if they do not offload */
64 	u32			*rx_crcp;
65 };
66 
67 struct iscsi_tcp_task {
68 	uint32_t		exp_datasn;	/* expected target's R2TSN/DataSN */
69 	int			data_offset;
70 	struct iscsi_r2t_info	*r2t;		/* in progress solict R2T */
71 	struct iscsi_pool	r2tpool;
72 	struct kfifo		r2tqueue;
73 	void			*dd_data;
74 	spinlock_t		pool2queue;
75 	spinlock_t		queue2pool;
76 };
77 
78 enum {
79 	ISCSI_TCP_SEGMENT_DONE,		/* curr seg has been processed */
80 	ISCSI_TCP_SKB_DONE,		/* skb is out of data */
81 	ISCSI_TCP_CONN_ERR,		/* iscsi layer has fired a conn err */
82 	ISCSI_TCP_SUSPENDED,		/* conn is suspended */
83 };
84 
85 extern void iscsi_tcp_hdr_recv_prep(struct iscsi_tcp_conn *tcp_conn);
86 extern int iscsi_tcp_recv_skb(struct iscsi_conn *conn, struct sk_buff *skb,
87 			      unsigned int offset, bool offloaded, int *status);
88 extern void iscsi_tcp_cleanup_task(struct iscsi_task *task);
89 extern int iscsi_tcp_task_init(struct iscsi_task *task);
90 extern int iscsi_tcp_task_xmit(struct iscsi_task *task);
91 
92 /* segment helpers */
93 extern int iscsi_tcp_recv_segment_is_hdr(struct iscsi_tcp_conn *tcp_conn);
94 extern int iscsi_tcp_segment_done(struct iscsi_tcp_conn *tcp_conn,
95 				  struct iscsi_segment *segment, int recv,
96 				  unsigned copied);
97 extern void iscsi_tcp_segment_unmap(struct iscsi_segment *segment);
98 
99 extern void iscsi_segment_init_linear(struct iscsi_segment *segment,
100 				      void *data, size_t size,
101 				      iscsi_segment_done_fn_t *done, u32 *crcp);
102 extern int
103 iscsi_segment_seek_sg(struct iscsi_segment *segment,
104 		      struct scatterlist *sg_list, unsigned int sg_count,
105 		      unsigned int offset, size_t size,
106 		      iscsi_segment_done_fn_t *done, u32 *crcp);
107 
108 /* digest helpers */
109 extern void iscsi_tcp_dgst_header(const void *hdr, size_t hdrlen,
110 				  unsigned char digest[ISCSI_DIGEST_SIZE]);
111 extern struct iscsi_cls_conn *
112 iscsi_tcp_conn_setup(struct iscsi_cls_session *cls_session, int dd_data_size,
113 		     uint32_t conn_idx);
114 extern void iscsi_tcp_conn_teardown(struct iscsi_cls_conn *cls_conn);
115 
116 /* misc helpers */
117 extern int iscsi_tcp_r2tpool_alloc(struct iscsi_session *session);
118 extern void iscsi_tcp_r2tpool_free(struct iscsi_session *session);
119 extern int iscsi_tcp_set_max_r2t(struct iscsi_conn *conn, char *buf);
120 extern void iscsi_tcp_conn_get_stats(struct iscsi_cls_conn *cls_conn,
121 				     struct iscsi_stats *stats);
122 #endif /* LIBISCSI_TCP_H */
123