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
23struct 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 */
59enum 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
70enum 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 */
86enum 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 */
97static 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 */
105static 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 */
113static 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 */
121static inline int fc_sof_is_init(enum fc_sof sof)
122{
123	return sof < 0x30;
124}
125
126#endif /* _FC_ENCAPS_H_ */
127