/include/scsi/fc_frame.h

  1/*
  2 * Copyright(c) 2007 Intel Corporation. All rights reserved.
  3 *
  4 * This program is free software; you can redistribute it and/or modify it
  5 * under the terms and conditions of the GNU General Public License,
  6 * version 2, as published by the Free Software Foundation.
  7 *
  8 * This program is distributed in the hope it will be useful, but WITHOUT
  9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 10 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 11 * more details.
 12 *
 13 * You should have received a copy of the GNU General Public License along with
 14 * this program; if not, write to the Free Software Foundation, Inc.,
 15 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
 16 *
 17 * Maintained at www.Open-FCoE.org
 18 */
 19
 20#ifndef _FC_FRAME_H_
 21#define _FC_FRAME_H_
 22
 23#include <linux/scatterlist.h>
 24#include <linux/skbuff.h>
 25#include <scsi/scsi_cmnd.h>
 26
 27#include <scsi/fc/fc_fs.h>
 28#include <scsi/fc/fc_fcp.h>
 29#include <scsi/fc/fc_encaps.h>
 30
 31#include <linux/if_ether.h>
 32
 33/*
 34 * The fc_frame interface is used to pass frame data between functions.
 35 * The frame includes the data buffer, length, and SOF / EOF delimiter types.
 36 * A pointer to the port structure of the receiving port is also includeded.
 37 */
 38
 39#define	FC_FRAME_HEADROOM	32	/* headroom for VLAN + FCoE headers */
 40#define	FC_FRAME_TAILROOM	8	/* trailer space for FCoE */
 41
 42/* Max number of skb frags allowed, reserving one for fcoe_crc_eof page */
 43#define FC_FRAME_SG_LEN		(MAX_SKB_FRAGS - 1)
 44
 45#define fp_skb(fp)	(&((fp)->skb))
 46#define fr_hdr(fp)	((fp)->skb.data)
 47#define fr_len(fp)	((fp)->skb.len)
 48#define fr_cb(fp)	((struct fcoe_rcv_info *)&((fp)->skb.cb[0]))
 49#define fr_dev(fp)	(fr_cb(fp)->fr_dev)
 50#define fr_seq(fp)	(fr_cb(fp)->fr_seq)
 51#define fr_sof(fp)	(fr_cb(fp)->fr_sof)
 52#define fr_eof(fp)	(fr_cb(fp)->fr_eof)
 53#define fr_flags(fp)	(fr_cb(fp)->fr_flags)
 54#define fr_max_payload(fp)	(fr_cb(fp)->fr_max_payload)
 55#define fr_fsp(fp)	(fr_cb(fp)->fr_fsp)
 56#define fr_crc(fp)	(fr_cb(fp)->fr_crc)
 57
 58struct fc_frame {
 59	struct sk_buff skb;
 60};
 61
 62struct fcoe_rcv_info {
 63	struct packet_type  *ptype;
 64	struct fc_lport	*fr_dev;	/* transport layer private pointer */
 65	struct fc_seq	*fr_seq;	/* for use with exchange manager */
 66	struct fc_fcp_pkt *fr_fsp;	/* for the corresponding fcp I/O */
 67	u32		fr_crc;
 68	u16		fr_max_payload;	/* max FC payload */
 69	enum fc_sof	fr_sof;		/* start of frame delimiter */
 70	enum fc_eof	fr_eof;		/* end of frame delimiter */
 71	u8		fr_flags;	/* flags - see below */
 72	u8		granted_mac[ETH_ALEN]; /* FCoE MAC address */
 73};
 74
 75
 76/*
 77 * Get fc_frame pointer for an skb that's already been imported.
 78 */
 79static inline struct fcoe_rcv_info *fcoe_dev_from_skb(const struct sk_buff *skb)
 80{
 81	BUILD_BUG_ON(sizeof(struct fcoe_rcv_info) > sizeof(skb->cb));
 82	return (struct fcoe_rcv_info *) skb->cb;
 83}
 84
 85/*
 86 * fr_flags.
 87 */
 88#define	FCPHF_CRC_UNCHECKED	0x01	/* CRC not computed, still appended */
 89
 90/*
 91 * Initialize a frame.
 92 * We don't do a complete memset here for performance reasons.
 93 * The caller must set fr_free, fr_hdr, fr_len, fr_sof, and fr_eof eventually.
 94 */
 95static inline void fc_frame_init(struct fc_frame *fp)
 96{
 97	fr_dev(fp) = NULL;
 98	fr_seq(fp) = NULL;
 99	fr_flags(fp) = 0;
100}
101
102struct fc_frame *fc_frame_alloc_fill(struct fc_lport *, size_t payload_len);
103struct fc_frame *_fc_frame_alloc(size_t payload_len);
104
105/*
106 * Allocate fc_frame structure and buffer.  Set the initial length to
107 * payload_size + sizeof (struct fc_frame_header).
108 */
109static inline struct fc_frame *fc_frame_alloc(struct fc_lport *dev, size_t len)
110{
111	struct fc_frame *fp;
112
113	/*
114	 * Note: Since len will often be a constant multiple of 4,
115	 * this check will usually be evaluated and eliminated at compile time.
116	 */
117	if (len && len % 4)
118		fp = fc_frame_alloc_fill(dev, len);
119	else
120		fp = _fc_frame_alloc(len);
121	return fp;
122}
123
124/*
125 * Free the fc_frame structure and buffer.
126 */
127static inline void fc_frame_free(struct fc_frame *fp)
128{
129	kfree_skb(fp_skb(fp));
130}
131
132static inline int fc_frame_is_linear(struct fc_frame *fp)
133{
134	return !skb_is_nonlinear(fp_skb(fp));
135}
136
137/*
138 * Get frame header from message in fc_frame structure.
139 * This hides a cast and provides a place to add some checking.
140 */
141static inline
142struct fc_frame_header *fc_frame_header_get(const struct fc_frame *fp)
143{
144	WARN_ON(fr_len(fp) < sizeof(struct fc_frame_header));
145	return (struct fc_frame_header *) fr_hdr(fp);
146}
147
148/*
149 * Get frame payload from message in fc_frame structure.
150 * This hides a cast and provides a place to add some checking.
151 * The len parameter is the minimum length for the payload portion.
152 * Returns NULL if the frame is too short.
153 *
154 * This assumes the interesting part of the payload is in the first part
155 * of the buffer for received data.  This may not be appropriate to use for
156 * buffers being transmitted.
157 */
158static inline void *fc_frame_payload_get(const struct fc_frame *fp,
159					 size_t len)
160{
161	void *pp = NULL;
162
163	if (fr_len(fp) >= sizeof(struct fc_frame_header) + len)
164		pp = fc_frame_header_get(fp) + 1;
165	return pp;
166}
167
168/*
169 * Get frame payload opcode (first byte) from message in fc_frame structure.
170 * This hides a cast and provides a place to add some checking. Return 0
171 * if the frame has no payload.
172 */
173static inline u8 fc_frame_payload_op(const struct fc_frame *fp)
174{
175	u8 *cp;
176
177	cp = fc_frame_payload_get(fp, sizeof(u8));
178	if (!cp)
179		return 0;
180	return *cp;
181
182}
183
184/*
185 * Get FC class from frame.
186 */
187static inline enum fc_class fc_frame_class(const struct fc_frame *fp)
188{
189	return fc_sof_class(fr_sof(fp));
190}
191
192/*
193 * Check the CRC in a frame.
194 * The CRC immediately follows the last data item *AFTER* the length.
195 * The return value is zero if the CRC matches.
196 */
197u32 fc_frame_crc_check(struct fc_frame *);
198
199static inline u8 fc_frame_rctl(const struct fc_frame *fp)
200{
201	return fc_frame_header_get(fp)->fh_r_ctl;
202}
203
204static inline bool fc_frame_is_cmd(const struct fc_frame *fp)
205{
206	return fc_frame_rctl(fp) == FC_RCTL_DD_UNSOL_CMD;
207}
208
209/*
210 * Check for leaks.
211 * Print the frame header of any currently allocated frame, assuming there
212 * should be none at this point.
213 */
214void fc_frame_leak_check(void);
215
216#endif /* _FC_FRAME_H_ */