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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_cmd(fp) (fr_cb(fp)->fr_cmd)
58#define fr_dir(fp) (fr_cmd(fp)->sc_data_direction)
59#define fr_crc(fp) (fr_cb(fp)->fr_crc)
60
61struct fc_frame {
62 struct sk_buff skb;
63};
64
65struct fcoe_rcv_info {
66 struct packet_type *ptype;
67 struct fc_lport *fr_dev; /* transport layer private pointer */
68 struct fc_seq *fr_seq; /* for use with exchange manager */
69 struct scsi_cmnd *fr_cmd; /* for use of scsi command */
70 u32 fr_crc;
71 u16 fr_max_payload; /* max FC payload */
72 enum fc_sof fr_sof; /* start of frame delimiter */
73 enum fc_eof fr_eof; /* end of frame delimiter */
74 u8 fr_flags; /* flags - see below */
75};
76
77
78/*
79 * Get fc_frame pointer for an skb that's already been imported.
80 */
81static inline struct fcoe_rcv_info *fcoe_dev_from_skb(const struct sk_buff *skb)
82{
83 BUILD_BUG_ON(sizeof(struct fcoe_rcv_info) > sizeof(skb->cb));
84 return (struct fcoe_rcv_info *) skb->cb;
85}
86
87/*
88 * fr_flags.
89 */
90#define FCPHF_CRC_UNCHECKED 0x01 /* CRC not computed, still appended */
91
92/*
93 * Initialize a frame.
94 * We don't do a complete memset here for performance reasons.
95 * The caller must set fr_free, fr_hdr, fr_len, fr_sof, and fr_eof eventually.
96 */
97static inline void fc_frame_init(struct fc_frame *fp)
98{
99 fr_dev(fp) = NULL;
100 fr_seq(fp) = NULL;
101 fr_flags(fp) = 0;
102}
103
104struct fc_frame *fc_frame_alloc_fill(struct fc_lport *, size_t payload_len);
105
106struct fc_frame *__fc_frame_alloc(size_t payload_len);
107
108/*
109 * Get frame for sending via port.
110 */
111static inline struct fc_frame *_fc_frame_alloc(struct fc_lport *dev,
112 size_t payload_len)
113{
114 return __fc_frame_alloc(payload_len);
115}
116
117/*
118 * Allocate fc_frame structure and buffer. Set the initial length to
119 * payload_size + sizeof (struct fc_frame_header).
120 */
121static inline struct fc_frame *fc_frame_alloc(struct fc_lport *dev, size_t len)
122{
123 struct fc_frame *fp;
124
125 /*
126 * Note: Since len will often be a constant multiple of 4,
127 * this check will usually be evaluated and eliminated at compile time.
128 */
129 if ((len % 4) != 0)
130 fp = fc_frame_alloc_fill(dev, len);
131 else
132 fp = _fc_frame_alloc(dev, len);
133 return fp;
134}
135
136/*
137 * Free the fc_frame structure and buffer.
138 */
139static inline void fc_frame_free(struct fc_frame *fp)
140{
141 kfree_skb(fp_skb(fp));
142}
143
144static inline int fc_frame_is_linear(struct fc_frame *fp)
145{
146 return !skb_is_nonlinear(fp_skb(fp));
147}
148
149/*
150 * Get frame header from message in fc_frame structure.
151 * This hides a cast and provides a place to add some checking.
152 */
153static inline
154struct fc_frame_header *fc_frame_header_get(const struct fc_frame *fp)
155{
156 WARN_ON(fr_len(fp) < sizeof(struct fc_frame_header));
157 return (struct fc_frame_header *) fr_hdr(fp);
158}
159
160/*
161 * Get frame payload from message in fc_frame structure.
162 * This hides a cast and provides a place to add some checking.
163 * The len parameter is the minimum length for the payload portion.
164 * Returns NULL if the frame is too short.
165 *
166 * This assumes the interesting part of the payload is in the first part
167 * of the buffer for received data. This may not be appropriate to use for
168 * buffers being transmitted.
169 */
170static inline void *fc_frame_payload_get(const struct fc_frame *fp,
171 size_t len)
172{
173 void *pp = NULL;
174
175 if (fr_len(fp) >= sizeof(struct fc_frame_header) + len)
176 pp = fc_frame_header_get(fp) + 1;
177 return pp;
178}
179
180/*
181 * Get frame payload opcode (first byte) from message in fc_frame structure.
182 * This hides a cast and provides a place to add some checking. Return 0
183 * if the frame has no payload.
184 */
185static inline u8 fc_frame_payload_op(const struct fc_frame *fp)
186{
187 u8 *cp;
188
189 cp = fc_frame_payload_get(fp, sizeof(u8));
190 if (!cp)
191 return 0;
192 return *cp;
193
194}
195
196/*
197 * Get FC class from frame.
198 */
199static inline enum fc_class fc_frame_class(const struct fc_frame *fp)
200{
201 return fc_sof_class(fr_sof(fp));
202}
203
204/*
205 * Check the CRC in a frame.
206 * The CRC immediately follows the last data item *AFTER* the length.
207 * The return value is zero if the CRC matches.
208 */
209u32 fc_frame_crc_check(struct fc_frame *);
210
211static inline u8 fc_frame_rctl(const struct fc_frame *fp)
212{
213 return fc_frame_header_get(fp)->fh_r_ctl;
214}
215
216static inline bool fc_frame_is_cmd(const struct fc_frame *fp)
217{
218 return fc_frame_rctl(fp) == FC_RCTL_DD_UNSOL_CMD;
219}
220
221static inline bool fc_frame_is_read(const struct fc_frame *fp)
222{
223 if (fc_frame_is_cmd(fp) && fr_cmd(fp))
224 return fr_dir(fp) == DMA_FROM_DEVICE;
225 return false;
226}
227
228static inline bool fc_frame_is_write(const struct fc_frame *fp)
229{
230 if (fc_frame_is_cmd(fp) && fr_cmd(fp))
231 return fr_dir(fp) == DMA_TO_DEVICE;
232 return false;
233}
234
235/*
236 * Check for leaks.
237 * Print the frame header of any currently allocated frame, assuming there
238 * should be none at this point.
239 */
240void fc_frame_leak_check(void);
241
242#endif /* _FC_FRAME_H_ */