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