Root/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/* some helpful macros */
34
35#define ntohll(x) be64_to_cpu(x)
36#define htonll(x) cpu_to_be64(x)
37
38static inline u32 ntoh24(const u8 *p)
39{
40    return (p[0] << 16) | (p[1] << 8) | p[2];
41}
42
43static inline void hton24(u8 *p, u32 v)
44{
45    p[0] = (v >> 16) & 0xff;
46    p[1] = (v >> 8) & 0xff;
47    p[2] = v & 0xff;
48}
49
50/*
51 * The fc_frame interface is used to pass frame data between functions.
52 * The frame includes the data buffer, length, and SOF / EOF delimiter types.
53 * A pointer to the port structure of the receiving port is also includeded.
54 */
55
56#define FC_FRAME_HEADROOM 32 /* headroom for VLAN + FCoE headers */
57#define FC_FRAME_TAILROOM 8 /* trailer space for FCoE */
58
59/* Max number of skb frags allowed, reserving one for fcoe_crc_eof page */
60#define FC_FRAME_SG_LEN (MAX_SKB_FRAGS - 1)
61
62#define fp_skb(fp) (&((fp)->skb))
63#define fr_hdr(fp) ((fp)->skb.data)
64#define fr_len(fp) ((fp)->skb.len)
65#define fr_cb(fp) ((struct fcoe_rcv_info *)&((fp)->skb.cb[0]))
66#define fr_dev(fp) (fr_cb(fp)->fr_dev)
67#define fr_seq(fp) (fr_cb(fp)->fr_seq)
68#define fr_sof(fp) (fr_cb(fp)->fr_sof)
69#define fr_eof(fp) (fr_cb(fp)->fr_eof)
70#define fr_flags(fp) (fr_cb(fp)->fr_flags)
71#define fr_encaps(fp) (fr_cb(fp)->fr_encaps)
72#define fr_max_payload(fp) (fr_cb(fp)->fr_max_payload)
73#define fr_fsp(fp) (fr_cb(fp)->fr_fsp)
74#define fr_crc(fp) (fr_cb(fp)->fr_crc)
75
76struct fc_frame {
77    struct sk_buff skb;
78};
79
80struct fcoe_rcv_info {
81    struct packet_type *ptype;
82    struct fc_lport *fr_dev; /* transport layer private pointer */
83    struct fc_seq *fr_seq; /* for use with exchange manager */
84    struct fc_fcp_pkt *fr_fsp; /* for the corresponding fcp I/O */
85    u32 fr_crc;
86    u16 fr_max_payload; /* max FC payload */
87    u8 fr_sof; /* start of frame delimiter */
88    u8 fr_eof; /* end of frame delimiter */
89    u8 fr_flags; /* flags - see below */
90    u8 fr_encaps; /* LLD encapsulation info (e.g. FIP) */
91    u8 granted_mac[ETH_ALEN]; /* FCoE MAC address */
92};
93
94
95/*
96 * Get fc_frame pointer for an skb that's already been imported.
97 */
98static inline struct fcoe_rcv_info *fcoe_dev_from_skb(const struct sk_buff *skb)
99{
100    BUILD_BUG_ON(sizeof(struct fcoe_rcv_info) > sizeof(skb->cb));
101    return (struct fcoe_rcv_info *) skb->cb;
102}
103
104/*
105 * fr_flags.
106 */
107#define FCPHF_CRC_UNCHECKED 0x01 /* CRC not computed, still appended */
108
109/*
110 * Initialize a frame.
111 * We don't do a complete memset here for performance reasons.
112 * The caller must set fr_free, fr_hdr, fr_len, fr_sof, and fr_eof eventually.
113 */
114static inline void fc_frame_init(struct fc_frame *fp)
115{
116    fr_dev(fp) = NULL;
117    fr_seq(fp) = NULL;
118    fr_flags(fp) = 0;
119    fr_encaps(fp) = 0;
120}
121
122struct fc_frame *fc_frame_alloc_fill(struct fc_lport *, size_t payload_len);
123struct fc_frame *_fc_frame_alloc(size_t payload_len);
124
125/*
126 * Allocate fc_frame structure and buffer. Set the initial length to
127 * payload_size + sizeof (struct fc_frame_header).
128 */
129static inline struct fc_frame *fc_frame_alloc(struct fc_lport *dev, size_t len)
130{
131    struct fc_frame *fp;
132
133    /*
134     * Note: Since len will often be a constant multiple of 4,
135     * this check will usually be evaluated and eliminated at compile time.
136     */
137    if (len && len % 4)
138        fp = fc_frame_alloc_fill(dev, len);
139    else
140        fp = _fc_frame_alloc(len);
141    return fp;
142}
143
144/*
145 * Free the fc_frame structure and buffer.
146 */
147static inline void fc_frame_free(struct fc_frame *fp)
148{
149    kfree_skb(fp_skb(fp));
150}
151
152static inline int fc_frame_is_linear(struct fc_frame *fp)
153{
154    return !skb_is_nonlinear(fp_skb(fp));
155}
156
157/*
158 * Get frame header from message in fc_frame structure.
159 * This version doesn't do a length check.
160 */
161static inline
162struct fc_frame_header *__fc_frame_header_get(const struct fc_frame *fp)
163{
164    return (struct fc_frame_header *)fr_hdr(fp);
165}
166
167/*
168 * Get frame header from message in fc_frame structure.
169 * This hides a cast and provides a place to add some checking.
170 */
171static inline
172struct fc_frame_header *fc_frame_header_get(const struct fc_frame *fp)
173{
174    WARN_ON(fr_len(fp) < sizeof(struct fc_frame_header));
175    return __fc_frame_header_get(fp);
176}
177
178/*
179 * Get source FC_ID (S_ID) from frame header in message.
180 */
181static inline u32 fc_frame_sid(const struct fc_frame *fp)
182{
183    return ntoh24(__fc_frame_header_get(fp)->fh_s_id);
184}
185
186/*
187 * Get destination FC_ID (D_ID) from frame header in message.
188 */
189static inline u32 fc_frame_did(const struct fc_frame *fp)
190{
191    return ntoh24(__fc_frame_header_get(fp)->fh_d_id);
192}
193
194/*
195 * Get frame payload from message in fc_frame structure.
196 * This hides a cast and provides a place to add some checking.
197 * The len parameter is the minimum length for the payload portion.
198 * Returns NULL if the frame is too short.
199 *
200 * This assumes the interesting part of the payload is in the first part
201 * of the buffer for received data. This may not be appropriate to use for
202 * buffers being transmitted.
203 */
204static inline void *fc_frame_payload_get(const struct fc_frame *fp,
205                     size_t len)
206{
207    void *pp = NULL;
208
209    if (fr_len(fp) >= sizeof(struct fc_frame_header) + len)
210        pp = fc_frame_header_get(fp) + 1;
211    return pp;
212}
213
214/*
215 * Get frame payload opcode (first byte) from message in fc_frame structure.
216 * This hides a cast and provides a place to add some checking. Return 0
217 * if the frame has no payload.
218 */
219static inline u8 fc_frame_payload_op(const struct fc_frame *fp)
220{
221    u8 *cp;
222
223    cp = fc_frame_payload_get(fp, sizeof(u8));
224    if (!cp)
225        return 0;
226    return *cp;
227
228}
229
230/*
231 * Get FC class from frame.
232 */
233static inline enum fc_class fc_frame_class(const struct fc_frame *fp)
234{
235    return fc_sof_class(fr_sof(fp));
236}
237
238/*
239 * Check the CRC in a frame.
240 * The CRC immediately follows the last data item *AFTER* the length.
241 * The return value is zero if the CRC matches.
242 */
243u32 fc_frame_crc_check(struct fc_frame *);
244
245static inline u8 fc_frame_rctl(const struct fc_frame *fp)
246{
247    return fc_frame_header_get(fp)->fh_r_ctl;
248}
249
250static inline bool fc_frame_is_cmd(const struct fc_frame *fp)
251{
252    return fc_frame_rctl(fp) == FC_RCTL_DD_UNSOL_CMD;
253}
254
255/*
256 * Check for leaks.
257 * Print the frame header of any currently allocated frame, assuming there
258 * should be none at this point.
259 */
260void fc_frame_leak_check(void);
261
262#endif /* _FC_FRAME_H_ */
263

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