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 struct ahash_request;
19 
20 typedef int iscsi_segment_done_fn_t(struct iscsi_tcp_conn *,
21 				    struct iscsi_segment *);
22 
23 struct iscsi_segment {
24 	unsigned char		*data;
25 	unsigned int		size;
26 	unsigned int		copied;
27 	unsigned int		total_size;
28 	unsigned int		total_copied;
29 
30 	struct ahash_request	*hash;
31 	unsigned char		padbuf[ISCSI_PAD_LEN];
32 	unsigned char		recv_digest[ISCSI_DIGEST_SIZE];
33 	unsigned char		digest[ISCSI_DIGEST_SIZE];
34 	unsigned int		digest_len;
35 
36 	struct scatterlist	*sg;
37 	void			*sg_mapped;
38 	unsigned int		sg_offset;
39 	bool			atomic_mapped;
40 
41 	iscsi_segment_done_fn_t	*done;
42 };
43 
44 /* Socket connection receive helper */
45 struct iscsi_tcp_recv {
46 	struct iscsi_hdr	*hdr;
47 	struct iscsi_segment	segment;
48 
49 	/* Allocate buffer for BHS + AHS */
50 	uint32_t		hdr_buf[64];
51 
52 	/* copied and flipped values */
53 	int			datalen;
54 };
55 
56 struct iscsi_tcp_conn {
57 	struct iscsi_conn	*iscsi_conn;
58 	void			*dd_data;
59 	int			stop_stage;	/* conn_stop() flag: *
60 						 * stop to recover,  *
61 						 * stop to terminate */
62 	/* control data */
63 	struct iscsi_tcp_recv	in;		/* TCP receive context */
64 	/* CRC32C (Rx) LLD should set this is they do not offload */
65 	struct ahash_request	*rx_hash;
66 };
67 
68 struct iscsi_tcp_task {
69 	uint32_t		exp_datasn;	/* expected target's R2TSN/DataSN */
70 	int			data_offset;
71 	struct iscsi_r2t_info	*r2t;		/* in progress solict R2T */
72 	struct iscsi_pool	r2tpool;
73 	struct kfifo		r2tqueue;
74 	void			*dd_data;
75 	spinlock_t		pool2queue;
76 	spinlock_t		queue2pool;
77 };
78 
79 enum {
80 	ISCSI_TCP_SEGMENT_DONE,		/* curr seg has been processed */
81 	ISCSI_TCP_SKB_DONE,		/* skb is out of data */
82 	ISCSI_TCP_CONN_ERR,		/* iscsi layer has fired a conn err */
83 	ISCSI_TCP_SUSPENDED,		/* conn is suspended */
84 };
85 
86 extern void iscsi_tcp_hdr_recv_prep(struct iscsi_tcp_conn *tcp_conn);
87 extern int iscsi_tcp_recv_skb(struct iscsi_conn *conn, struct sk_buff *skb,
88 			      unsigned int offset, bool offloaded, int *status);
89 extern void iscsi_tcp_cleanup_task(struct iscsi_task *task);
90 extern int iscsi_tcp_task_init(struct iscsi_task *task);
91 extern int iscsi_tcp_task_xmit(struct iscsi_task *task);
92 
93 /* segment helpers */
94 extern int iscsi_tcp_recv_segment_is_hdr(struct iscsi_tcp_conn *tcp_conn);
95 extern int iscsi_tcp_segment_done(struct iscsi_tcp_conn *tcp_conn,
96 				  struct iscsi_segment *segment, int recv,
97 				  unsigned copied);
98 extern void iscsi_tcp_segment_unmap(struct iscsi_segment *segment);
99 
100 extern void iscsi_segment_init_linear(struct iscsi_segment *segment,
101 				      void *data, size_t size,
102 				      iscsi_segment_done_fn_t *done,
103 				      struct ahash_request *hash);
104 extern int
105 iscsi_segment_seek_sg(struct iscsi_segment *segment,
106 		      struct scatterlist *sg_list, unsigned int sg_count,
107 		      unsigned int offset, size_t size,
108 		      iscsi_segment_done_fn_t *done,
109 		      struct ahash_request *hash);
110 
111 /* digest helpers */
112 extern void iscsi_tcp_dgst_header(struct ahash_request *hash, const void *hdr,
113 				  size_t hdrlen,
114 				  unsigned char digest[ISCSI_DIGEST_SIZE]);
115 extern struct iscsi_cls_conn *
116 iscsi_tcp_conn_setup(struct iscsi_cls_session *cls_session, int dd_data_size,
117 		     uint32_t conn_idx);
118 extern void iscsi_tcp_conn_teardown(struct iscsi_cls_conn *cls_conn);
119 
120 /* misc helpers */
121 extern int iscsi_tcp_r2tpool_alloc(struct iscsi_session *session);
122 extern void iscsi_tcp_r2tpool_free(struct iscsi_session *session);
123 extern int iscsi_tcp_set_max_r2t(struct iscsi_conn *conn, char *buf);
124 extern void iscsi_tcp_conn_get_stats(struct iscsi_cls_conn *cls_conn,
125 				     struct iscsi_stats *stats);
126 #endif /* LIBISCSI_TCP_H */
127