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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/*
32 * The fc_frame interface is used to pass frame data between functions.
33 * The frame includes the data buffer, length, and SOF / EOF delimiter types.
34 * A pointer to the port structure of the receiving port is also includeded.
35 */
36
37#define FC_FRAME_HEADROOM 32 /* headroom for VLAN + FCoE headers */
38#define FC_FRAME_TAILROOM 8 /* trailer space for FCoE */
39
40/*
41 * Information about an individual fibre channel frame received or to be sent.
42 * The buffer may be in up to 4 additional non-contiguous sections,
43 * but the linear section must hold the frame header.
44 */
45#define FC_FRAME_SG_LEN 4 /* scatter/gather list maximum length */
46
47#define fp_skb(fp) (&((fp)->skb))
48#define fr_hdr(fp) ((fp)->skb.data)
49#define fr_len(fp) ((fp)->skb.len)
50#define fr_cb(fp) ((struct fcoe_rcv_info *)&((fp)->skb.cb[0]))
51#define fr_dev(fp) (fr_cb(fp)->fr_dev)
52#define fr_seq(fp) (fr_cb(fp)->fr_seq)
53#define fr_sof(fp) (fr_cb(fp)->fr_sof)
54#define fr_eof(fp) (fr_cb(fp)->fr_eof)
55#define fr_flags(fp) (fr_cb(fp)->fr_flags)
56#define fr_max_payload(fp) (fr_cb(fp)->fr_max_payload)
57#define fr_fsp(fp) (fr_cb(fp)->fr_fsp)
58#define fr_crc(fp) (fr_cb(fp)->fr_crc)
59
60struct fc_frame {
61 struct sk_buff skb;
62};
63
64struct fcoe_rcv_info {
65 struct packet_type *ptype;
66 struct fc_lport *fr_dev; /* transport layer private pointer */
67 struct fc_seq *fr_seq; /* for use with exchange manager */
68 struct fc_fcp_pkt *fr_fsp; /* for the corresponding fcp I/O */
69 u32 fr_crc;
70 u16 fr_max_payload; /* max FC payload */
71 enum fc_sof fr_sof; /* start of frame delimiter */
72 enum fc_eof fr_eof; /* end of frame delimiter */
73 u8 fr_flags; /* flags - see below */
74};
75
76
77/*
78 * Get fc_frame pointer for an skb that's already been imported.
79 */
80static inline struct fcoe_rcv_info *fcoe_dev_from_skb(const struct sk_buff *skb)
81{
82 BUILD_BUG_ON(sizeof(struct fcoe_rcv_info) > sizeof(skb->cb));
83 return (struct fcoe_rcv_info *) skb->cb;
84}
85
86/*
87 * fr_flags.
88 */
89#define FCPHF_CRC_UNCHECKED 0x01 /* CRC not computed, still appended */
90
91/*
92 * Initialize a frame.
93 * We don't do a complete memset here for performance reasons.
94 * The caller must set fr_free, fr_hdr, fr_len, fr_sof, and fr_eof eventually.
95 */
96static inline void fc_frame_init(struct fc_frame *fp)
97{
98 fr_dev(fp) = NULL;
99 fr_seq(fp) = NULL;
100 fr_flags(fp) = 0;
101}
102
103struct fc_frame *fc_frame_alloc_fill(struct fc_lport *, size_t payload_len);
104
105struct fc_frame *__fc_frame_alloc(size_t payload_len);
106
107/*
108 * Get frame for sending via port.
109 */
110static inline struct fc_frame *_fc_frame_alloc(struct fc_lport *dev,
111 size_t payload_len)
112{
113 return __fc_frame_alloc(payload_len);
114}
115
116/*
117 * Allocate fc_frame structure and buffer. Set the initial length to
118 * payload_size + sizeof (struct fc_frame_header).
119 */
120static inline struct fc_frame *fc_frame_alloc(struct fc_lport *dev, size_t len)
121{
122 struct fc_frame *fp;
123
124 /*
125 * Note: Since len will often be a constant multiple of 4,
126 * this check will usually be evaluated and eliminated at compile time.
127 */
128 if ((len % 4) != 0)
129 fp = fc_frame_alloc_fill(dev, len);
130 else
131 fp = _fc_frame_alloc(dev, len);
132 return fp;
133}
134
135/*
136 * Free the fc_frame structure and buffer.
137 */
138static inline void fc_frame_free(struct fc_frame *fp)
139{
140 kfree_skb(fp_skb(fp));
141}
142
143static inline int fc_frame_is_linear(struct fc_frame *fp)
144{
145 return !skb_is_nonlinear(fp_skb(fp));
146}
147
148/*
149 * Get frame header from message in fc_frame structure.
150 * This hides a cast and provides a place to add some checking.
151 */
152static inline
153struct fc_frame_header *fc_frame_header_get(const struct fc_frame *fp)
154{
155 WARN_ON(fr_len(fp) < sizeof(struct fc_frame_header));
156 return (struct fc_frame_header *) fr_hdr(fp);
157}
158
159/*
160 * Get frame payload from message in fc_frame structure.
161 * This hides a cast and provides a place to add some checking.
162 * The len parameter is the minimum length for the payload portion.
163 * Returns NULL if the frame is too short.
164 *
165 * This assumes the interesting part of the payload is in the first part
166 * of the buffer for received data. This may not be appropriate to use for
167 * buffers being transmitted.
168 */
169static inline void *fc_frame_payload_get(const struct fc_frame *fp,
170 size_t len)
171{
172 void *pp = NULL;
173
174 if (fr_len(fp) >= sizeof(struct fc_frame_header) + len)
175 pp = fc_frame_header_get(fp) + 1;
176 return pp;
177}
178
179/*
180 * Get frame payload opcode (first byte) from message in fc_frame structure.
181 * This hides a cast and provides a place to add some checking. Return 0
182 * if the frame has no payload.
183 */
184static inline u8 fc_frame_payload_op(const struct fc_frame *fp)
185{
186 u8 *cp;
187
188 cp = fc_frame_payload_get(fp, sizeof(u8));
189 if (!cp)
190 return 0;
191 return *cp;
192
193}
194
195/*
196 * Get FC class from frame.
197 */
198static inline enum fc_class fc_frame_class(const struct fc_frame *fp)
199{
200 return fc_sof_class(fr_sof(fp));
201}
202
203/*
204 * Check the CRC in a frame.
205 * The CRC immediately follows the last data item *AFTER* the length.
206 * The return value is zero if the CRC matches.
207 */
208u32 fc_frame_crc_check(struct fc_frame *);
209
210static inline u8 fc_frame_rctl(const struct fc_frame *fp)
211{
212 return fc_frame_header_get(fp)->fh_r_ctl;
213}
214
215static inline bool fc_frame_is_cmd(const struct fc_frame *fp)
216{
217 return fc_frame_rctl(fp) == FC_RCTL_DD_UNSOL_CMD;
218}
219
220/*
221 * Check for leaks.
222 * Print the frame header of any currently allocated frame, assuming there
223 * should be none at this point.
224 */
225void fc_frame_leak_check(void);
226
227#endif /* _FC_FRAME_H_ */