libiscsi_tcp.h

  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
 15struct iscsi_tcp_conn;
 16struct iscsi_segment;
 17struct sk_buff;
 18
 19typedef int iscsi_segment_done_fn_t(struct iscsi_tcp_conn *,
 20				    struct iscsi_segment *);
 21
 22struct 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 */
 44struct 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
 55struct 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
 67struct 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
 78enum {
 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
 85extern void iscsi_tcp_hdr_recv_prep(struct iscsi_tcp_conn *tcp_conn);
 86extern int iscsi_tcp_recv_skb(struct iscsi_conn *conn, struct sk_buff *skb,
 87			      unsigned int offset, bool offloaded, int *status);
 88extern void iscsi_tcp_cleanup_task(struct iscsi_task *task);
 89extern int iscsi_tcp_task_init(struct iscsi_task *task);
 90extern int iscsi_tcp_task_xmit(struct iscsi_task *task);
 91
 92/* segment helpers */
 93extern int iscsi_tcp_recv_segment_is_hdr(struct iscsi_tcp_conn *tcp_conn);
 94extern int iscsi_tcp_segment_done(struct iscsi_tcp_conn *tcp_conn,
 95				  struct iscsi_segment *segment, int recv,
 96				  unsigned copied);
 97extern void iscsi_tcp_segment_unmap(struct iscsi_segment *segment);
 98
 99extern void iscsi_segment_init_linear(struct iscsi_segment *segment,
100				      void *data, size_t size,
101				      iscsi_segment_done_fn_t *done, u32 *crcp);
102extern int
103iscsi_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 */
109extern void iscsi_tcp_dgst_header(const void *hdr, size_t hdrlen,
110				  unsigned char digest[ISCSI_DIGEST_SIZE]);
111extern struct iscsi_cls_conn *
112iscsi_tcp_conn_setup(struct iscsi_cls_session *cls_session, int dd_data_size,
113		     uint32_t conn_idx);
114extern void iscsi_tcp_conn_teardown(struct iscsi_cls_conn *cls_conn);
115
116/* misc helpers */
117extern int iscsi_tcp_r2tpool_alloc(struct iscsi_session *session);
118extern void iscsi_tcp_r2tpool_free(struct iscsi_session *session);
119extern int iscsi_tcp_set_max_r2t(struct iscsi_conn *conn, char *buf);
120extern void iscsi_tcp_conn_get_stats(struct iscsi_cls_conn *cls_conn,
121				     struct iscsi_stats *stats);
122#endif /* LIBISCSI_TCP_H */