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 #ifndef _FC_ENCAPS_H_
20 #define _FC_ENCAPS_H_
21 
22 /*
23  * Protocol definitions from RFC 3643 - Fibre Channel Frame Encapsulation.
24  *
25  * Note:  The frame length field is the number of 32-bit words in
26  * the encapsulation including the fcip_encaps_header, CRC and EOF words.
27  * The minimum frame length value in bytes is (32 + 24 + 4 + 4) * 4 = 64.
28  * The maximum frame length value in bytes is (32 + 24 + 2112 + 4 + 4) = 2172.
29  */
30 #define FC_ENCAPS_MIN_FRAME_LEN 64	/* min frame len (bytes) (see above) */
31 #define FC_ENCAPS_MAX_FRAME_LEN (FC_ENCAPS_MIN_FRAME_LEN + FC_MAX_PAYLOAD)
32 
33 #define FC_ENCAPS_VER       1           /* current version number */
34 
35 struct fc_encaps_hdr {
36 	__u8	fc_proto;	/* protocol number */
37 	__u8	fc_ver;		/* version of encapsulation */
38 	__u8	fc_proto_n;	/* ones complement of protocol */
39 	__u8	fc_ver_n;	/* ones complement of version */
40 
41 	unsigned char fc_proto_data[8]; /* protocol specific data */
42 
43 	__be16	fc_len_flags;	/* 10-bit length/4 w/ 6 flag bits */
44 	__be16	fc_len_flags_n;	/* ones complement of length / flags */
45 
46 	/*
47 	 * Offset 0x10
48 	 */
49 	__be32	fc_time[2];	/* time stamp: seconds and fraction */
50 	__be32	fc_crc;		/* CRC */
51 	__be32	fc_sof;		/* start of frame (see FC_SOF below) */
52 
53 	/* 0x20 - FC frame content followed by EOF word */
54 };
55 
56 #define FCIP_ENCAPS_HDR_LEN 0x20	/* expected length for asserts */
57 
58 /*
59  * Macro's for making redundant copies of EOF and SOF.
60  */
61 #define FC_XY(x, y)		((((x) & 0xff) << 8) | ((y) & 0xff))
62 #define FC_XYXY(x, y)		((FCIP_XY(x, y) << 16) | FCIP_XY(x, y))
63 #define FC_XYNN(x, y)		(FCIP_XYXY(x, y) ^ 0xffff)
64 
65 #define FC_SOF_ENCODE(n)	FC_XYNN(n, n)
66 #define FC_EOF_ENCODE(n)	FC_XYNN(n, n)
67 
68 /*
69  * SOF / EOF bytes.
70  */
71 enum fc_sof {
72 	FC_SOF_F =	0x28,	/* fabric */
73 	FC_SOF_I4 =	0x29,	/* initiate class 4 */
74 	FC_SOF_I2 =	0x2d,	/* initiate class 2 */
75 	FC_SOF_I3 =	0x2e,	/* initiate class 3 */
76 	FC_SOF_N4 =	0x31,	/* normal class 4 */
77 	FC_SOF_N2 =	0x35,	/* normal class 2 */
78 	FC_SOF_N3 =	0x36,	/* normal class 3 */
79 	FC_SOF_C4 =	0x39,	/* activate class 4 */
80 } __attribute__((packed));
81 
82 enum fc_eof {
83 	FC_EOF_N =	0x41,	/* normal (not last frame of seq) */
84 	FC_EOF_T =	0x42,	/* terminate (last frame of sequence) */
85 	FC_EOF_RT =	0x44,
86 	FC_EOF_DT =	0x46,	/* disconnect-terminate class-1 */
87 	FC_EOF_NI =	0x49,	/* normal-invalid */
88 	FC_EOF_DTI =	0x4e,	/* disconnect-terminate-invalid */
89 	FC_EOF_RTI =	0x4f,
90 	FC_EOF_A =	0x50,	/* abort */
91 } __attribute__((packed));
92 
93 #define FC_SOF_CLASS_MASK 0x06	/* mask for class of service in SOF */
94 
95 /*
96  * Define classes in terms of the SOF code (initial).
97  */
98 enum fc_class {
99 	FC_CLASS_NONE = 0,	/* software value indicating no class */
100 	FC_CLASS_2 =	FC_SOF_I2,
101 	FC_CLASS_3 =	FC_SOF_I3,
102 	FC_CLASS_4 =	FC_SOF_I4,
103 	FC_CLASS_F =	FC_SOF_F,
104 };
105 
106 /*
107  * Determine whether SOF code indicates the need for a BLS ACK.
108  */
fc_sof_needs_ack(enum fc_sof sof)109 static inline int fc_sof_needs_ack(enum fc_sof sof)
110 {
111 	return (~sof) & 0x02;	/* true for class 1, 2, 4, 6, or F */
112 }
113 
114 /*
115  * Given an fc_class, return the normal (non-initial) SOF value.
116  */
fc_sof_normal(enum fc_class class)117 static inline enum fc_sof fc_sof_normal(enum fc_class class)
118 {
119 	return class + FC_SOF_N3 - FC_SOF_I3;	/* diff is always 8 */
120 }
121 
122 /*
123  * Compute class from SOF value.
124  */
fc_sof_class(enum fc_sof sof)125 static inline enum fc_class fc_sof_class(enum fc_sof sof)
126 {
127 	return (sof & 0x7) | FC_SOF_F;
128 }
129 
130 /*
131  * Determine whether SOF is for the initial frame of a sequence.
132  */
fc_sof_is_init(enum fc_sof sof)133 static inline int fc_sof_is_init(enum fc_sof sof)
134 {
135 	return sof < 0x30;
136 }
137 
138 #endif /* _FC_ENCAPS_H_ */
139