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  */
fc_sof_needs_ack(enum fc_sof sof)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  */
fc_sof_normal(enum fc_class class)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  */
fc_sof_class(enum fc_sof sof)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  */
fc_sof_is_init(enum fc_sof sof)121 static inline int fc_sof_is_init(enum fc_sof sof)
122 {
123 	return sof < 0x30;
124 }
125 
126 #endif /* _FC_ENCAPS_H_ */
127