fc_encaps.h

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/*
 * Copyright(c) 2007 Intel Corporation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Maintained at www.Open-FCoE.org
 */
#ifndef _FC_ENCAPS_H_
#define _FC_ENCAPS_H_

/*
 * Protocol definitions from RFC 3643 - Fibre Channel Frame Encapsulation.
 *
 * Note:  The frame length field is the number of 32-bit words in
 * the encapsulation including the fcip_encaps_header, CRC and EOF words.
 * The minimum frame length value in bytes is (32 + 24 + 4 + 4) * 4 = 64.
 * The maximum frame length value in bytes is (32 + 24 + 2112 + 4 + 4) = 2172.
 */
#define FC_ENCAPS_MIN_FRAME_LEN 64  /* min frame len (bytes) (see above) */
#define FC_ENCAPS_MAX_FRAME_LEN (FC_ENCAPS_MIN_FRAME_LEN + FC_MAX_PAYLOAD)

#define FC_ENCAPS_VER       1           /* current version number */

struct fc_encaps_hdr {
    __u8    fc_proto;   /* protocol number */
    __u8    fc_ver;     /* version of encapsulation */
    __u8    fc_proto_n; /* ones complement of protocol */
    __u8    fc_ver_n;   /* ones complement of version */

    unsigned char fc_proto_data[8]; /* protocol specific data */

    __be16  fc_len_flags;   /* 10-bit length/4 w/ 6 flag bits */
    __be16  fc_len_flags_n; /* ones complement of length / flags */

    /*
     * Offset 0x10
     */
    __be32  fc_time[2]; /* time stamp: seconds and fraction */
    __be32  fc_crc;     /* CRC */
    __be32  fc_sof;     /* start of frame (see FC_SOF below) */

    /* 0x20 - FC frame content followed by EOF word */
};

#define FCIP_ENCAPS_HDR_LEN 0x20    /* expected length for asserts */

/*
 * Macro's for making redundant copies of EOF and SOF.
 */
#define FC_XY(x, y)     ((((x) & 0xff) << 8) | ((y) & 0xff))
#define FC_XYXY(x, y)       ((FCIP_XY(x, y) << 16) | FCIP_XY(x, y))
#define FC_XYNN(x, y)       (FCIP_XYXY(x, y) ^ 0xffff)

#define FC_SOF_ENCODE(n)    FC_XYNN(n, n)
#define FC_EOF_ENCODE(n)    FC_XYNN(n, n)

/*
 * SOF / EOF bytes.
 */
enum fc_sof {
    FC_SOF_F =  0x28,   /* fabric */
    FC_SOF_I4 = 0x29,   /* initiate class 4 */
    FC_SOF_I2 = 0x2d,   /* initiate class 2 */
    FC_SOF_I3 = 0x2e,   /* initiate class 3 */
    FC_SOF_N4 = 0x31,   /* normal class 4 */
    FC_SOF_N2 = 0x35,   /* normal class 2 */
    FC_SOF_N3 = 0x36,   /* normal class 3 */
    FC_SOF_C4 = 0x39,   /* activate class 4 */
} __attribute__((packed));

enum fc_eof {
    FC_EOF_N =  0x41,   /* normal (not last frame of seq) */
    FC_EOF_T =  0x42,   /* terminate (last frame of sequence) */
    FC_EOF_RT = 0x44,
    FC_EOF_DT = 0x46,   /* disconnect-terminate class-1 */
    FC_EOF_NI = 0x49,   /* normal-invalid */
    FC_EOF_DTI =    0x4e,   /* disconnect-terminate-invalid */
    FC_EOF_RTI =    0x4f,
    FC_EOF_A =  0x50,   /* abort */
} __attribute__((packed));

#define FC_SOF_CLASS_MASK 0x06  /* mask for class of service in SOF */

/*
 * Define classes in terms of the SOF code (initial).
 */
enum fc_class {
    FC_CLASS_NONE = 0,  /* software value indicating no class */
    FC_CLASS_2 =    FC_SOF_I2,
    FC_CLASS_3 =    FC_SOF_I3,
    FC_CLASS_4 =    FC_SOF_I4,
    FC_CLASS_F =    FC_SOF_F,
};

/*
 * Determine whether SOF code indicates the need for a BLS ACK.
 */
static inline int fc_sof_needs_ack(enum fc_sof sof)
{
    return (~sof) & 0x02;   /* true for class 1, 2, 4, 6, or F */
}

/*
 * Given an fc_class, return the normal (non-initial) SOF value.
 */
static inline enum fc_sof fc_sof_normal(enum fc_class class)
{
    return class + FC_SOF_N3 - FC_SOF_I3;   /* diff is always 8 */
}

/*
 * Compute class from SOF value.
 */
static inline enum fc_class fc_sof_class(enum fc_sof sof)
{
    return (sof & 0x7) | FC_SOF_F;
}

/*
 * Determine whether SOF is for the initial frame of a sequence.
 */
static inline int fc_sof_is_init(enum fc_sof sof)
{
    return sof < 0x30;
}

#endif /* _FC_ENCAPS_H_ */