include/scsi/fc/fc_encaps.h

   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_ */