include/scsi/fc/fc_encaps.h

   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  */
 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  */
 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  */
 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  */
 133 static inline int fc_sof_is_init(enum fc_sof sof)
 134 {
 135         return sof < 0x30;
 136 }
 137
 138 #endif /* _FC_ENCAPS_H_ */