1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * Copyright(c) 2007 Intel Corporation. All rights reserved.
4 *
5 * Maintained at www.Open-FCoE.org
6 */
7 #ifndef _FC_ENCAPS_H_
8 #define _FC_ENCAPS_H_
9
10 /*
11 * Protocol definitions from RFC 3643 - Fibre Channel Frame Encapsulation.
12 *
13 * Note: The frame length field is the number of 32-bit words in
14 * the encapsulation including the fcip_encaps_header, CRC and EOF words.
15 * The minimum frame length value in bytes is (32 + 24 + 4 + 4) * 4 = 64.
16 * The maximum frame length value in bytes is (32 + 24 + 2112 + 4 + 4) = 2172.
17 */
18 #define FC_ENCAPS_MIN_FRAME_LEN 64 /* min frame len (bytes) (see above) */
19 #define FC_ENCAPS_MAX_FRAME_LEN (FC_ENCAPS_MIN_FRAME_LEN + FC_MAX_PAYLOAD)
20
21 #define FC_ENCAPS_VER 1 /* current version number */
22
23 struct fc_encaps_hdr {
24 __u8 fc_proto; /* protocol number */
25 __u8 fc_ver; /* version of encapsulation */
26 __u8 fc_proto_n; /* ones complement of protocol */
27 __u8 fc_ver_n; /* ones complement of version */
28
29 unsigned char fc_proto_data[8]; /* protocol specific data */
30
31 __be16 fc_len_flags; /* 10-bit length/4 w/ 6 flag bits */
32 __be16 fc_len_flags_n; /* ones complement of length / flags */
33
34 /*
35 * Offset 0x10
36 */
37 __be32 fc_time[2]; /* time stamp: seconds and fraction */
38 __be32 fc_crc; /* CRC */
39 __be32 fc_sof; /* start of frame (see FC_SOF below) */
40
41 /* 0x20 - FC frame content followed by EOF word */
42 };
43
44 #define FCIP_ENCAPS_HDR_LEN 0x20 /* expected length for asserts */
45
46 /*
47 * Macro's for making redundant copies of EOF and SOF.
48 */
49 #define FC_XY(x, y) ((((x) & 0xff) << 8) | ((y) & 0xff))
50 #define FC_XYXY(x, y) ((FCIP_XY(x, y) << 16) | FCIP_XY(x, y))
51 #define FC_XYNN(x, y) (FCIP_XYXY(x, y) ^ 0xffff)
52
53 #define FC_SOF_ENCODE(n) FC_XYNN(n, n)
54 #define FC_EOF_ENCODE(n) FC_XYNN(n, n)
55
56 /*
57 * SOF / EOF bytes.
58 */
59 enum fc_sof {
60 FC_SOF_F = 0x28, /* fabric */
61 FC_SOF_I4 = 0x29, /* initiate class 4 */
62 FC_SOF_I2 = 0x2d, /* initiate class 2 */
63 FC_SOF_I3 = 0x2e, /* initiate class 3 */
64 FC_SOF_N4 = 0x31, /* normal class 4 */
65 FC_SOF_N2 = 0x35, /* normal class 2 */
66 FC_SOF_N3 = 0x36, /* normal class 3 */
67 FC_SOF_C4 = 0x39, /* activate class 4 */
68 } __attribute__((packed));
69
70 enum fc_eof {
71 FC_EOF_N = 0x41, /* normal (not last frame of seq) */
72 FC_EOF_T = 0x42, /* terminate (last frame of sequence) */
73 FC_EOF_RT = 0x44,
74 FC_EOF_DT = 0x46, /* disconnect-terminate class-1 */
75 FC_EOF_NI = 0x49, /* normal-invalid */
76 FC_EOF_DTI = 0x4e, /* disconnect-terminate-invalid */
77 FC_EOF_RTI = 0x4f,
78 FC_EOF_A = 0x50, /* abort */
79 } __attribute__((packed));
80
81 #define FC_SOF_CLASS_MASK 0x06 /* mask for class of service in SOF */
82
83 /*
84 * Define classes in terms of the SOF code (initial).
85 */
86 enum fc_class {
87 FC_CLASS_NONE = 0, /* software value indicating no class */
88 FC_CLASS_2 = FC_SOF_I2,
89 FC_CLASS_3 = FC_SOF_I3,
90 FC_CLASS_4 = FC_SOF_I4,
91 FC_CLASS_F = FC_SOF_F,
92 };
93
94 /*
95 * Determine whether SOF code indicates the need for a BLS ACK.
96 */
97 static inline int fc_sof_needs_ack(enum fc_sof sof)
98 {
99 return (~sof) & 0x02; /* true for class 1, 2, 4, 6, or F */
100 }
101
102 /*
103 * Given an fc_class, return the normal (non-initial) SOF value.
104 */
105 static inline enum fc_sof fc_sof_normal(enum fc_class class)
106 {
107 return class + FC_SOF_N3 - FC_SOF_I3; /* diff is always 8 */
108 }
109
110 /*
111 * Compute class from SOF value.
112 */
113 static inline enum fc_class fc_sof_class(enum fc_sof sof)
114 {
115 return (sof & 0x7) | FC_SOF_F;
116 }
117
118 /*
119 * Determine whether SOF is for the initial frame of a sequence.
120 */
121 static inline int fc_sof_is_init(enum fc_sof sof)
122 {
123 return sof < 0x30;
124 }
125
126 #endif /* _FC_ENCAPS_H_ */