path: root/epan/dissectors/packet-fcp.c

/* packet-fcp.c
 * Routines for Fibre Channel Protocol for SCSI (FCP)
 * Copyright 2001, Dinesh G Dutt <ddutt@cisco.com>
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 */

#include "config.h"

#include <epan/packet.h>
#include <epan/conversation.h>
#include <epan/proto_data.h>
#include <epan/tfs.h>
#include "packet-scsi.h"
#include "packet-fc.h"
#include "packet-fcels.h"

void proto_register_fcp(void);
void proto_reg_handoff_fcp(void);

static dissector_handle_t fcp_handle;

typedef struct _fcp_proto_data_t {
    uint16_t lun;
} fcp_proto_data_t;

/* Initialize the protocol and registered fields */
static int proto_fcp;
static int hf_fcp_multilun;
static int hf_fcp_singlelun;
static int hf_fcp_crn;
static int hf_fcp_taskattr;
static int hf_fcp_taskmgmt;
static int hf_fcp_addlcdblen;
static int hf_fcp_rddata;
static int hf_fcp_wrdata;
static int hf_fcp_dl;
static int hf_fcp_bidir_dl;
static int hf_fcp_data_ro;
static int hf_fcp_r_ctl;
static int hf_fcp_burstlen;
static int hf_fcp_rspflags;
static int hf_fcp_retry_delay_timer;
static int hf_fcp_resid;
static int hf_fcp_bidir_resid;
static int hf_fcp_snslen;
static int hf_fcp_rsplen;
static int hf_fcp_rspcode;
static int hf_fcp_scsistatus;
static int hf_fcp_mgmt_flags_obsolete;
static int hf_fcp_mgmt_flags_clear_aca;
static int hf_fcp_mgmt_flags_target_reset;
static int hf_fcp_mgmt_flags_lu_reset;
static int hf_fcp_mgmt_flags_rsvd;
static int hf_fcp_mgmt_flags_clear_task_set;
static int hf_fcp_mgmt_flags_abort_task_set;
static int hf_fcp_rsp_flags_bidi;
static int hf_fcp_rsp_flags_bidi_rru;
static int hf_fcp_rsp_flags_bidi_rro;
static int hf_fcp_rsp_flags_conf_req;
static int hf_fcp_rsp_flags_resid_under;
static int hf_fcp_rsp_flags_resid_over;
static int hf_fcp_rsp_flags_sns_vld;
static int hf_fcp_rsp_flags_res_vld;
static int hf_fcp_request_in;
static int hf_fcp_response_in;
static int hf_fcp_time;
static int hf_fcp_els_op;
static int hf_fcp_srr_ox_id;
static int hf_fcp_srr_rx_id;

/* Initialize the subtree pointers */
static int ett_fcp;
static int ett_fcp_taskmgmt;
static int ett_fcp_rsp_flags;

typedef struct _fcp_conv_data_t {
    wmem_map_t *luns;
} fcp_conv_data_t;

typedef struct fcp_request_data {
   uint32_t request_frame;
   uint32_t response_frame;
   nstime_t request_time;
   itlq_nexus_t *itlq;
} fcp_request_data_t;

#define FCP_DEF_CMND_LEN         32 /* by default cmnd is 32 bytes */
#define FCP_DEF_RSP_LEN          24 /* default FCP_RSP len */

/* Information Categories based on lower 4 bits of R_CTL */
#define FCP_IU_DATA              0x1
#define FCP_IU_UNSOL_CTL         0x2
#define FCP_IU_SOL_CTL           0x3
#define FCP_IU_CONFIRM           0x3
#define FCP_IU_XFER_RDY          0x5
#define FCP_IU_CMD               0x6
#define FCP_IU_RSP               0x7

static const value_string fcp_iu_val[] = {
    {FCP_IU_DATA      , "FCP_DATA"},
    {FCP_IU_UNSOL_CTL , "Control"},
    {FCP_IU_CONFIRM   , "Confirm"},
    {FCP_IU_XFER_RDY  , "XFER_RDY"},
    {FCP_IU_CMD       , "FCP_CMND"},
    {FCP_IU_RSP       , "FCP_RSP"},
    {0, NULL},
};


/* Task Attribute Values */
static const value_string fcp_task_attr_val[] = {
    {0, "Simple"},
    {1, "Head of Queue"},
    {2, "Ordered"},
    {4, "ACA"},
    {5, "Untagged"},
    {0, NULL},
};

/* RSP Code Definitions (from FCP_RSP_INFO) */
static const value_string fcp_rsp_code_val[] = {
    {0, "Task Management Function Complete"},
    {1, "FCP_DATA length Different from FCP_BURST_LEN"},
    {2, "FCP_CMND Fields Invalid"},
    {3, "FCP_DATA Parameter Mismatch With FCP_DATA_RO"},
    {4, "Task Management Function Rejected"},
    {5, "Task Management Function Failed"},
    {9, "Task Management Function Incorrect LUN"},
    {0, NULL},
};



static const true_false_string fcp_mgmt_flags_obsolete_tfs = {
   "OBSOLETE BIT is SET",
   "OBSOLETE BIT is NOT set",
};
static const true_false_string fcp_mgmt_flags_clear_aca_tfs = {
   "CLEAR ACA is SET",
   "Clear aca is NOT set",
};
static const true_false_string fcp_mgmt_flags_target_reset_tfs = {
   "TARGET RESET is SET",
   "Target reset is NOT set",
};
static const true_false_string fcp_mgmt_flags_lu_reset_tfs = {
   "LU RESET is SET",
   "Lu reset is NOT set",
};
static const true_false_string fcp_mgmt_flags_rsvd_tfs = {
   "RSVD is SET",
   "Rsvd is NOT set",
};
static const true_false_string fcp_mgmt_flags_clear_task_set_tfs = {
   "CLEAR TASK SET is SET",
   "Clear task set is NOT set",
};
static const true_false_string fcp_mgmt_flags_abort_task_set_tfs = {
   "ABORT TASK SET is SET",
   "Abort task set is NOT set",
};

static void
dissect_task_mgmt_flags(packet_info *pinfo, proto_tree *parent_tree, tvbuff_t *tvb, int offset)
{
    proto_item *item;
    static int * const mgmt_flags[] = {
        &hf_fcp_mgmt_flags_obsolete,
        &hf_fcp_mgmt_flags_clear_aca,
        &hf_fcp_mgmt_flags_target_reset,
        &hf_fcp_mgmt_flags_lu_reset,
        &hf_fcp_mgmt_flags_rsvd,
        &hf_fcp_mgmt_flags_clear_task_set,
        &hf_fcp_mgmt_flags_abort_task_set,
        NULL
    };

    uint8_t flags;

    flags = tvb_get_uint8(tvb, offset);
    item = proto_tree_add_bitmask_with_flags(parent_tree, tvb, offset, hf_fcp_taskmgmt,
                                   ett_fcp_taskmgmt, mgmt_flags, ENC_NA, BMT_NO_FALSE|BMT_NO_TFS);

    if (!flags)
        proto_item_append_text(item, " (No values set)");

    if (flags & 0x80) {
        col_prepend_fence_fstr(pinfo->cinfo, COL_INFO, "[FCP OBSOLETE] ");
    }

    if (flags & 0x40) {
        col_prepend_fence_fstr(pinfo->cinfo, COL_INFO, "[FCP CLEAR_ACA] ");
    }

    if (flags & 0x20) {
        col_prepend_fence_fstr(pinfo->cinfo, COL_INFO, "[FCP TARGET_RESET] ");
    }

    if (flags & 0x10) {
        col_prepend_fence_fstr(pinfo->cinfo, COL_INFO, "[FCP LU_RESET] ");
    }

    if (flags & 0x08) {
        col_prepend_fence_fstr(pinfo->cinfo, COL_INFO, "[FCP RSVD] ");
    }

    if (flags & 0x04) {
        col_prepend_fence_fstr(pinfo->cinfo, COL_INFO, "[FCP CLEAR_TASK_SET] ");
    }

    if (flags & 0x02) {
        col_prepend_fence_fstr(pinfo->cinfo, COL_INFO, "[FCP ABORT_TASK_SET] ");
    }
}

static const true_false_string fcp_rsp_flags_bidi_tfs = {
   "Bidirectional residual fields are PRESENT",
   "Bidirectional residual fields are NOT present",
};
static const true_false_string fcp_rsp_flags_bidi_rru_tfs = {
   "Bidirectional residual underflow is PRESENT",
   "Bidirectional residual underflow is NOT present",
};
static const true_false_string fcp_rsp_flags_bidi_rro_tfs = {
   "Bidirectional residual overflow is PRESENT",
   "Bidirectional residual overflow is NOT present",
};
static const true_false_string fcp_rsp_flags_conf_req_tfs = {
   "CONF REQ is SET",
   "Conf req set is NOT set",
};
static const true_false_string fcp_rsp_flags_resid_under_tfs = {
   "RESID UNDER is SET",
   "Resid under is NOT set",
};
static const true_false_string fcp_rsp_flags_resid_over_tfs = {
   "RESID OVER is SET",
   "Resid over is NOT set",
};
static const true_false_string fcp_rsp_flags_sns_vld_tfs = {
   "SNS VLD is SET",
   "Sns vld is NOT set",
};
static const true_false_string fcp_rsp_flags_res_vld_tfs = {
   "RES VLD is SET",
   "Res vld is NOT set",
};

static void
dissect_rsp_flags(proto_tree *parent_tree, tvbuff_t *tvb, int offset)
{
    proto_item *item;
    uint8_t     flags;
    static int * const resid_present_flags[] = {
        &hf_fcp_rsp_flags_bidi,
        &hf_fcp_rsp_flags_bidi_rru,
        &hf_fcp_rsp_flags_bidi_rro,
        &hf_fcp_rsp_flags_conf_req,
        &hf_fcp_rsp_flags_resid_under,
        &hf_fcp_rsp_flags_resid_over,
        &hf_fcp_rsp_flags_sns_vld,
        &hf_fcp_rsp_flags_res_vld,
        NULL
    };

    static int * const no_resid_flags[] = {
        &hf_fcp_rsp_flags_bidi,
        &hf_fcp_rsp_flags_conf_req,
        &hf_fcp_rsp_flags_resid_under,
        &hf_fcp_rsp_flags_resid_over,
        &hf_fcp_rsp_flags_sns_vld,
        &hf_fcp_rsp_flags_res_vld,
        NULL
    };

    flags = tvb_get_uint8(tvb, offset);
    if (flags & 0x80) {
        item = proto_tree_add_bitmask_with_flags(parent_tree, tvb, offset, hf_fcp_rspflags,
                                   ett_fcp_rsp_flags, resid_present_flags, ENC_NA, BMT_NO_FALSE|BMT_NO_TFS);
    } else {
        item = proto_tree_add_bitmask_with_flags(parent_tree, tvb, offset, hf_fcp_rspflags,
                                   ett_fcp_rsp_flags, no_resid_flags, ENC_NA, BMT_NO_FALSE|BMT_NO_TFS);
    }

    if (!flags)
        proto_item_append_text(item, " (No values set)");
}

static void
dissect_fcp_cmnd(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, proto_tree *tree, conversation_t *conversation, fc_hdr *fchdr, fcp_conv_data_t *fcp_conv_data)
{
    int          offset  = 0;
    int          add_len = 0;
    uint8_t      flags, rwflags, lun0;
    uint16_t     lun     = 0xffff;
    tvbuff_t    *cdb_tvb;
    int          tvb_len;
    fcp_request_data_t *request_data = NULL;
    itl_nexus_t itl;
    fcp_proto_data_t *proto_data;

    /* Determine the length of the FCP part of the packet */
    flags = tvb_get_uint8(tvb, offset+10);
    if (flags) {
        add_len = tvb_get_uint8(tvb, offset+11) & 0x7C;
        add_len = add_len >> 2;
    }

    lun0 = tvb_get_uint8(tvb, offset);

    /* Display single-level LUNs in decimal for clarity */
    /* I'm taking a shortcut here by assuming that if the first byte of the
     * LUN field is 0, it is a single-level LUN. This is not true. For a
     * real single-level LUN, all 8 bytes except byte 1 must be 0.
     */
    if (lun0) {
      proto_tree_add_item(tree, hf_fcp_multilun, tvb, offset, 8, ENC_NA);
      lun = tvb_get_uint8(tvb, offset) & 0x3f;
      lun <<= 8;
      lun |= tvb_get_uint8(tvb, offset+1);
    } else {
      proto_tree_add_item(tree, hf_fcp_singlelun, tvb, offset+1,
                          1, ENC_BIG_ENDIAN);
      lun = tvb_get_uint8(tvb, offset+1);
    }

    if (!pinfo->fd->visited) {
        proto_data = wmem_new(wmem_file_scope(), fcp_proto_data_t);
        proto_data->lun = lun;
        p_add_proto_data(wmem_file_scope(), pinfo, proto_fcp, 0, proto_data);
    }

    request_data = (fcp_request_data_t*)wmem_map_lookup(fcp_conv_data->luns, GUINT_TO_POINTER((unsigned)lun));
    if (!request_data) {
        request_data = wmem_new(wmem_file_scope(), fcp_request_data_t);
        request_data->request_frame = pinfo->num;
        request_data->response_frame = 0;
        request_data->request_time = pinfo->abs_ts;

        request_data->itlq = wmem_new(wmem_file_scope(), itlq_nexus_t);
        request_data->itlq->first_exchange_frame=0;
        request_data->itlq->last_exchange_frame=0;
        request_data->itlq->lun=lun;
        request_data->itlq->scsi_opcode=0xffff;
        request_data->itlq->task_flags=0;
        request_data->itlq->data_length=0;
        request_data->itlq->bidir_data_length=0;
        request_data->itlq->fc_time=pinfo->abs_ts;
        request_data->itlq->flags=0;
        request_data->itlq->alloc_len=0;
        request_data->itlq->extra_data=NULL;

        wmem_map_insert(fcp_conv_data->luns, GUINT_TO_POINTER((unsigned)lun), request_data);
    }

    /* populate the exchange struct */
    if(!pinfo->fd->visited){
        if(fchdr->fctl&FC_FCTL_EXCHANGE_FIRST){
            request_data->itlq->first_exchange_frame=pinfo->num;
            request_data->itlq->fc_time = pinfo->abs_ts;
        }
        if(fchdr->fctl&FC_FCTL_EXCHANGE_LAST){
            request_data->itlq->last_exchange_frame=pinfo->num;
        }
    }

    if (request_data->itlq)
        request_data->itlq->lun = lun;

    fchdr->lun = lun;

    proto_tree_add_item(tree, hf_fcp_crn, tvb, offset+8, 1, ENC_BIG_ENDIAN);
    proto_tree_add_item(tree, hf_fcp_taskattr, tvb, offset+9, 1, ENC_BIG_ENDIAN);
    dissect_task_mgmt_flags(pinfo, tree, tvb, offset+10);
    proto_tree_add_item(tree, hf_fcp_addlcdblen, tvb, offset+11, 1, ENC_BIG_ENDIAN);
    rwflags = tvb_get_uint8(tvb, offset+11);
    if (request_data->itlq) {
        if (rwflags & 0x02) {
            request_data->itlq->task_flags |= SCSI_DATA_READ;
        }
        if (rwflags & 0x01) {
            request_data->itlq->task_flags |= SCSI_DATA_WRITE;
        }
    }
    proto_tree_add_item(tree, hf_fcp_rddata, tvb, offset+11, 1, ENC_BIG_ENDIAN);
    proto_tree_add_item(tree, hf_fcp_wrdata, tvb, offset+11, 1, ENC_BIG_ENDIAN);

    tvb_len = tvb_captured_length_remaining(tvb, offset+12);
    if (tvb_len > (16 + add_len))
      tvb_len = 16 + add_len;

    itl.cmdset = 0xff;
    itl.conversation = conversation;

    cdb_tvb = tvb_new_subset_length(tvb, offset+12, tvb_len);
    dissect_scsi_cdb(cdb_tvb, pinfo, parent_tree, SCSI_DEV_UNKNOWN, request_data->itlq, &itl);

    proto_tree_add_item(tree, hf_fcp_dl, tvb, offset+12+16+add_len,
                        4, ENC_BIG_ENDIAN);
    if (request_data->itlq) {
        request_data->itlq->data_length = tvb_get_ntohl(tvb, offset+12+16+add_len);
    }

    if ( ((rwflags & 0x03) == 0x03)
    &&  tvb_reported_length_remaining(tvb, offset+12+16+add_len+4) >= 4) {
        proto_tree_add_item(tree, hf_fcp_bidir_dl, tvb, offset+12+16+add_len+4,
                            4, ENC_BIG_ENDIAN);
        if (request_data->itlq) {
            request_data->itlq->bidir_data_length = tvb_get_ntohl(tvb, offset+12+16+add_len+4);
        }

    }

}

static void
dissect_fcp_data(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, conversation_t *conversation, itlq_nexus_t *itlq, uint32_t relative_offset)
{
    itl_nexus_t itl;
    itlq_nexus_t empty_itlq;

    itl.cmdset = 0xff;
    itl.conversation = conversation;

    if (itlq == NULL)
    {
        /* Provide "default" itlq */
        memset(&empty_itlq, 0, sizeof(empty_itlq));
        empty_itlq.lun=0xffff;
        empty_itlq.scsi_opcode=0xffff;
        itlq = &empty_itlq;
    }

    dissect_scsi_payload(tvb, pinfo, parent_tree, false, itlq, &itl, relative_offset);
}

/* fcp-3  9.5 table 24 */
static int
dissect_fcp_rspinfo(tvbuff_t *tvb, proto_tree *tree, int offset)
{
    /* 3 reserved bytes */
    offset += 3;

    /* rsp code */
    proto_tree_add_item(tree, hf_fcp_rspcode, tvb, offset, 1, ENC_BIG_ENDIAN);
    offset += 1;

    /* 4 reserved bytes */
    offset += 4;

    return offset;
}

static void
dissect_fcp_rsp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, proto_tree *tree, conversation_t *conversation, fc_hdr *fchdr, fcp_request_data_t *request_data)
{
    uint32_t    offset = 0;
    int32_t     snslen = 0;
    int32_t     rsplen = 0;
    uint8_t     flags;
    uint8_t     status;
    itl_nexus_t itl;
    itlq_nexus_t empty_itlq;

    status = tvb_get_uint8(tvb, offset+11);

    col_append_fstr(pinfo->cinfo, COL_INFO, ":%s",
                         val_to_str(status, scsi_status_val, "0x%x"));

    /* Save the response frame */
    if (request_data != NULL) {
        request_data->response_frame = pinfo->num;

        /* populate the exchange struct */
        if(!pinfo->fd->visited){
            if(fchdr->fctl&FC_FCTL_EXCHANGE_FIRST){
                request_data->itlq->first_exchange_frame=pinfo->num;
                request_data->itlq->fc_time = pinfo->abs_ts;
            }
            if(fchdr->fctl&FC_FCTL_EXCHANGE_LAST){
                request_data->itlq->last_exchange_frame=pinfo->num;
            }
        }
    } else {
        /* Provide "default" itlq */
        memset(&empty_itlq, 0, sizeof(empty_itlq));
        empty_itlq.lun=0xffff;
        empty_itlq.scsi_opcode=0xffff;
    }

    /* 8 reserved bytes */
    offset += 8;

    /* retry delay timer */
    proto_tree_add_item(tree, hf_fcp_retry_delay_timer, tvb, offset, 2, ENC_BIG_ENDIAN);
    offset += 2;

    /* flags */
    flags = tvb_get_uint8(tvb, offset);
    dissect_rsp_flags(tree, tvb, offset);
    offset += 1;

    itl.cmdset = 0xff;
    itl.conversation = conversation;

    /* scsi status code */
    proto_tree_add_item(tree, hf_fcp_scsistatus, tvb, offset, 1, ENC_BIG_ENDIAN);
    dissect_scsi_rsp(tvb, pinfo, parent_tree, (request_data != NULL) ? request_data->itlq : &empty_itlq, &itl, tvb_get_uint8(tvb, offset));
    offset += 1;

    /* residual count */
    if (flags & 0x0e) {
        proto_tree_add_item(tree, hf_fcp_resid, tvb, offset, 4, ENC_BIG_ENDIAN);
    }
    offset += 4;

    /* sense length */
    if (flags & 0x2) {
        snslen = tvb_get_ntohl(tvb, offset);
        proto_tree_add_uint(tree, hf_fcp_snslen, tvb, offset, 4,
                            snslen);
    }
    offset += 4;

    /* response length */
    if (flags & 0x1) {
        rsplen = tvb_get_ntohl(tvb, offset);
        proto_tree_add_uint(tree, hf_fcp_rsplen, tvb, offset, 4,
                            rsplen);
    }
    offset += 4;

    /* rsp_info */
    if (rsplen) {
        tvbuff_t *rspinfo_tvb;

        rspinfo_tvb = tvb_new_subset_length_caplen(tvb, offset, MIN(rsplen, tvb_captured_length_remaining(tvb, offset)), rsplen);
        dissect_fcp_rspinfo(rspinfo_tvb, tree, 0);

        offset += rsplen;
    }

    /* sense info */
    if (snslen) {
        tvbuff_t *sns_tvb;

        sns_tvb = tvb_new_subset_length_caplen(tvb, offset, MIN(snslen, tvb_captured_length_remaining(tvb, offset)), snslen);
        dissect_scsi_snsinfo(sns_tvb, pinfo, parent_tree, 0,
                              snslen,
                              (request_data != NULL) ? request_data->itlq : &empty_itlq, &itl);

        offset += snslen;
    }

    /* bidir read resid (only present for bidirectional responses) */
    if (flags & 0x80) {
        if (flags & 0x60) {
            proto_tree_add_item(tree, hf_fcp_bidir_resid, tvb, offset, 4, ENC_BIG_ENDIAN);
        }
        /*offset += 4;*/
    }
}

static void
dissect_fcp_xfer_rdy(tvbuff_t *tvb, proto_tree *tree)
{
    int         offset = 0;

    proto_tree_add_item(tree, hf_fcp_data_ro, tvb, offset, 4, ENC_BIG_ENDIAN);
    proto_tree_add_item(tree, hf_fcp_burstlen, tvb, offset+4, 4, ENC_BIG_ENDIAN);
}

static void
dissect_fcp_srr(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree, fc_hdr *fchdr)
{
    uint8_t r_ctl;

    r_ctl = fchdr->r_ctl & 0xf;
    if (r_ctl == FCP_IU_UNSOL_CTL) {            /* request */
        proto_tree_add_item(tree, hf_fcp_srr_ox_id, tvb, 4, 2, ENC_BIG_ENDIAN);
        proto_tree_add_item(tree, hf_fcp_srr_rx_id, tvb, 6, 2, ENC_BIG_ENDIAN);
        proto_tree_add_item(tree, hf_fcp_data_ro, tvb, 8, 4, ENC_BIG_ENDIAN);
        proto_tree_add_item(tree, hf_fcp_r_ctl, tvb, 12, 1, ENC_NA);
    }
}

static const value_string fcp_els_iu_val[] = {
    {FCP_IU_UNSOL_CTL   , "FCP ELS Request"},
    {FCP_IU_SOL_CTL     , "FCP ELS Response"},
    {0, NULL},
};

/*
 * Dissect FC-4 ELS for FCP.
 */
static void
dissect_fcp_els(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, fc_hdr *fchdr)
{
    uint8_t op;

    op = tvb_get_uint8(tvb, 0);
    col_add_str(pinfo->cinfo, COL_INFO, val_to_str_ext(op, &fc_els_proto_val_ext, "0x%x"));
    proto_tree_add_item(tree, hf_fcp_els_op, tvb, 0, 1, ENC_NA);

    switch (op) {   /* XXX should switch based on conv for LS_ACC */
    case FC_ELS_SRR:
        dissect_fcp_srr(tvb, pinfo, tree, fchdr);
        break;
    default:
        call_data_dissector(tvb, pinfo, tree);
        break;
    }
}

static int
dissect_fcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data)
{
    proto_item      *ti            = NULL;
    proto_tree      *fcp_tree      = NULL;
    fc_hdr          *fchdr;
    uint8_t          r_ctl;
    conversation_t  *fc_conv;
    fcp_conv_data_t *fcp_conv_data = NULL;
    fcp_request_data_t *request_data = NULL;
    bool             els;
    fcp_proto_data_t *proto_data;

    /* Reject the packet if data is NULL */
    if (data == NULL)
        return 0;
    fchdr = (fc_hdr *)data;

    /* Make entries in Protocol column and Info column on summary display */
    col_set_str(pinfo->cinfo, COL_PROTOCOL, "FCP");

    r_ctl = fchdr->r_ctl;
    els = (r_ctl & 0xf0) == FC_RCTL_LINK_DATA;
    r_ctl &= 0xF;

    col_add_str(pinfo->cinfo, COL_INFO,
                     val_to_str(r_ctl, els ? fcp_els_iu_val : fcp_iu_val,
                                 "0x%x"));

    ti = proto_tree_add_protocol_format(tree, proto_fcp, tvb, 0, -1,
                                            "FCP: %s",
                                            val_to_str(r_ctl,
                                            els ? fcp_els_iu_val :
                                            fcp_iu_val, "Unknown 0x%02x"));
    fcp_tree = proto_item_add_subtree(ti, ett_fcp);

    fc_conv = find_or_create_conversation(pinfo);
    fcp_conv_data = (fcp_conv_data_t *)conversation_get_proto_data(fc_conv, proto_fcp);

    if (!fcp_conv_data) {
        fcp_conv_data = wmem_new(wmem_file_scope(), fcp_conv_data_t);
        fcp_conv_data->luns = wmem_map_new(wmem_file_scope(), g_direct_hash, g_direct_equal);
        conversation_add_proto_data(fc_conv, proto_fcp, fcp_conv_data);
    }

    /* Lun is only populated by FCP_IU_CMD, and subsequent packets assume the same lun.
       The only way that consistently works is to save the lun on the first pass when packets
       are guaranteed to be parsed consecutively */
    if (!pinfo->fd->visited) {
        proto_data = wmem_new(wmem_file_scope(), fcp_proto_data_t);
        proto_data->lun = fchdr->lun;
        p_add_proto_data(wmem_file_scope(), pinfo, proto_fcp, 0, proto_data);
    } else {
        proto_data = (fcp_proto_data_t *)p_get_proto_data(wmem_file_scope(), pinfo, proto_fcp, 0);
    }

    if ((r_ctl != FCP_IU_CMD) && (r_ctl != FCP_IU_UNSOL_CTL) && (proto_data != NULL)) {
        request_data = (fcp_request_data_t *)wmem_map_lookup(fcp_conv_data->luns, GUINT_TO_POINTER((unsigned)(proto_data->lun)));
    }

    /* put a request_in in all frames except the command frame */
    if ((r_ctl != FCP_IU_CMD) && (r_ctl != FCP_IU_UNSOL_CTL) &&
        (request_data != NULL) && (request_data->itlq->first_exchange_frame)) {
        proto_item *it;
        it = proto_tree_add_uint(fcp_tree, hf_fcp_singlelun, tvb, 0, 0, proto_data->lun);
        proto_item_set_generated(it);
        if (request_data != NULL) {
            it = proto_tree_add_uint(fcp_tree, hf_fcp_request_in, tvb, 0, 0, request_data->request_frame);
            proto_item_set_generated(it);
            /* only put the response time in the actual response frame */
            if (r_ctl == FCP_IU_RSP) {
                nstime_t delta_ts;
                nstime_delta(&delta_ts, &pinfo->abs_ts, &request_data->request_time);
                it = proto_tree_add_time(ti, hf_fcp_time, tvb, 0, 0, &delta_ts);
                proto_item_set_generated(it);
            }
        }
    }
    /* put a response_in in all frames except the response frame */
    if ((r_ctl != FCP_IU_RSP) && (r_ctl != FCP_IU_SOL_CTL) &&
        (request_data != NULL) && (request_data->response_frame)) {
        proto_item *it;
        it = proto_tree_add_uint(fcp_tree, hf_fcp_response_in, tvb, 0, 0, request_data->response_frame);
        proto_item_set_generated(it);
    }

    if (els) {
        dissect_fcp_els(tvb, pinfo, fcp_tree, fchdr);
        return tvb_captured_length(tvb);
    }

    switch (r_ctl) {
    case FCP_IU_DATA:
        dissect_fcp_data(tvb, pinfo, tree, fc_conv, (request_data != NULL) ? request_data->itlq : NULL, fchdr->relative_offset);
        break;
    case FCP_IU_CONFIRM:
        /* Nothing to be done here */
        break;
    case FCP_IU_XFER_RDY:
        dissect_fcp_xfer_rdy(tvb, fcp_tree);
        break;
    case FCP_IU_CMD:
        dissect_fcp_cmnd(tvb, pinfo, tree, fcp_tree, fc_conv, fchdr, fcp_conv_data);
        break;
    case FCP_IU_RSP:
        dissect_fcp_rsp(tvb, pinfo, tree, fcp_tree, fc_conv, fchdr, request_data);
        break;
    default:
        call_data_dissector(tvb, pinfo, tree);
        break;
    }
/*xxx once the subdissectors return bytes consumed:  proto_item_set_end(ti, tvb, offset);*/
    return tvb_captured_length(tvb);
}

/* Register the protocol with Wireshark */

void
proto_register_fcp(void)
{

    /* Setup list of header fields  See Section 1.6.1 for details*/
    static hf_register_info hf[] = {
        { &hf_fcp_multilun,
          {"Multi-Level LUN", "fcp.multilun",
           FT_BYTES, BASE_NONE, NULL, 0x0,
           NULL, HFILL}},

        { &hf_fcp_singlelun,
          {"LUN", "fcp.lun",
           FT_UINT8, BASE_HEX, NULL, 0x0,
           NULL, HFILL}},

        { &hf_fcp_crn,
          {"Command Ref Num", "fcp.crn",
           FT_UINT8, BASE_DEC, NULL, 0x0,
           NULL, HFILL}},

        { &hf_fcp_taskattr,
          {"Task Attribute", "fcp.taskattr",
           FT_UINT8, BASE_HEX, VALS(fcp_task_attr_val), 0x7,
           NULL, HFILL}},

        { &hf_fcp_taskmgmt,
          {"Task Management Flags", "fcp.taskmgmt",
           FT_UINT8, BASE_HEX, NULL, 0x0,
           NULL, HFILL}},

        { &hf_fcp_addlcdblen,
          {"Additional CDB Length", "fcp.addlcdblen",
           FT_UINT8, BASE_DEC, NULL, 0xFC,
           NULL, HFILL}},

        { &hf_fcp_rddata,
          {"RDDATA", "fcp.rddata",
           FT_BOOLEAN, 8, NULL, 0x02,
           NULL, HFILL}},

        { &hf_fcp_wrdata,
          {"WRDATA", "fcp.wrdata",
           FT_BOOLEAN, 8, NULL, 0x01,
           NULL, HFILL}},

        { &hf_fcp_dl,
          {"FCP_DL", "fcp.dl",
           FT_UINT32, BASE_DEC, NULL, 0x0,
           NULL, HFILL}},

        { &hf_fcp_bidir_dl,
          {"FCP_BIDIRECTIONAL_READ_DL", "fcp.bidir_dl",
           FT_UINT32, BASE_DEC, NULL, 0x0,
           NULL, HFILL}},

        { &hf_fcp_data_ro,
          {"FCP_DATA_RO", "fcp.data_ro",
           FT_UINT32, BASE_DEC, VALS(fcp_iu_val), 0x0,
           NULL, HFILL}},

        { &hf_fcp_r_ctl,
          {"R_CTL", "fcp.r_ctl",
           FT_UINT8, BASE_HEX, NULL, 0x0,
           NULL, HFILL}},

        { &hf_fcp_burstlen,
          {"Burst Length", "fcp.burstlen",
           FT_UINT32, BASE_DEC, NULL, 0x0,
           NULL, HFILL}},

        { &hf_fcp_retry_delay_timer,
          {"Retry Delay Timer", "fcp.rsp.retry_delay_timer",
           FT_UINT16, BASE_DEC, NULL, 0x0,
           NULL, HFILL}},

        { &hf_fcp_rspflags,
          {"FCP_RSP Flags", "fcp.rspflags",
           FT_UINT8, BASE_HEX, NULL, 0x0,
           NULL, HFILL}},

        { &hf_fcp_resid,
          {"FCP_RESID", "fcp.resid",
           FT_UINT32, BASE_DEC, NULL, 0x0,
           NULL, HFILL}},

        { &hf_fcp_bidir_resid,
          {"Bidirectional Read Resid", "fcp.bidir_resid",
           FT_UINT32, BASE_DEC, NULL, 0x0,
           NULL, HFILL}},

        { &hf_fcp_snslen,
          {"FCP_SNS_LEN", "fcp.snslen",
           FT_UINT32, BASE_DEC, NULL, 0x0,
           NULL, HFILL}},

        { &hf_fcp_rsplen,
          {"FCP_RSP_LEN", "fcp.rsplen",
           FT_UINT32, BASE_DEC, NULL, 0x0,
           NULL, HFILL}},

        { &hf_fcp_rspcode,
          {"RSP_CODE", "fcp.rspcode",
           FT_UINT8, BASE_HEX, VALS(fcp_rsp_code_val), 0x0,
           NULL, HFILL}},

        { &hf_fcp_scsistatus,
          {"SCSI Status", "fcp.status",
           FT_UINT8, BASE_HEX, VALS(scsi_status_val), 0x0,
           NULL, HFILL}},

        { &hf_fcp_mgmt_flags_obsolete,
          { "Obsolete", "fcp.mgmt.flags.obsolete",
            FT_BOOLEAN, 8, TFS(&fcp_mgmt_flags_obsolete_tfs), 0x80,
            NULL, HFILL }},

        { &hf_fcp_mgmt_flags_clear_aca,
          { "Clear ACA", "fcp.mgmt.flags.clear_aca",
            FT_BOOLEAN, 8, TFS(&fcp_mgmt_flags_clear_aca_tfs), 0x40,
            NULL, HFILL }},

        { &hf_fcp_mgmt_flags_target_reset,
          { "Target Reset", "fcp.mgmt.flags.target_reset",
            FT_BOOLEAN, 8, TFS(&fcp_mgmt_flags_target_reset_tfs), 0x20,
            NULL, HFILL }},

        { &hf_fcp_mgmt_flags_lu_reset,
          { "LU Reset", "fcp.mgmt.flags.lu_reset",
            FT_BOOLEAN, 8, TFS(&fcp_mgmt_flags_lu_reset_tfs), 0x10,
            NULL, HFILL }},

        { &hf_fcp_mgmt_flags_rsvd,
          { "Rsvd", "fcp.mgmt.flags.rsvd",
            FT_BOOLEAN, 8, TFS(&fcp_mgmt_flags_rsvd_tfs), 0x08,
            NULL, HFILL }},

        { &hf_fcp_mgmt_flags_clear_task_set,
          { "Clear Task Set", "fcp.mgmt.flags.clear_task_set",
            FT_BOOLEAN, 8, TFS(&fcp_mgmt_flags_clear_task_set_tfs), 0x04,
            NULL, HFILL }},

        { &hf_fcp_mgmt_flags_abort_task_set,
          { "Abort Task Set", "fcp.mgmt.flags.abort_task_set",
            FT_BOOLEAN, 8, TFS(&fcp_mgmt_flags_abort_task_set_tfs), 0x02,
            NULL, HFILL }},

        { &hf_fcp_rsp_flags_bidi,
          { "Bidi Rsp", "fcp.rsp.flags.bidi",
            FT_BOOLEAN, 8, TFS(&fcp_rsp_flags_bidi_tfs), 0x80,
            NULL, HFILL }},

        { &hf_fcp_rsp_flags_bidi_rru,
          { "Bidi Read Resid Under", "fcp.rsp.flags.bidi_rru",
            FT_BOOLEAN, 8, TFS(&fcp_rsp_flags_bidi_rru_tfs), 0x40,
            NULL, HFILL }},

        { &hf_fcp_rsp_flags_bidi_rro,
          { "Bidi Read Resid Over", "fcp.rsp.flags.bidi_rro",
            FT_BOOLEAN, 8, TFS(&fcp_rsp_flags_bidi_rro_tfs), 0x20,
            NULL, HFILL }},

        { &hf_fcp_rsp_flags_conf_req,
          { "Conf Req", "fcp.rsp.flags.conf_req",
            FT_BOOLEAN, 8, TFS(&fcp_rsp_flags_conf_req_tfs), 0x10,
            NULL, HFILL }},

        { &hf_fcp_rsp_flags_resid_under,
          { "Resid Under", "fcp.rsp.flags.resid_under",
            FT_BOOLEAN, 8, TFS(&fcp_rsp_flags_resid_under_tfs), 0x08,
            NULL, HFILL }},

        { &hf_fcp_rsp_flags_resid_over,
          { "Resid Over", "fcp.rsp.flags.resid_over",
            FT_BOOLEAN, 8, TFS(&fcp_rsp_flags_resid_over_tfs), 0x04,
            NULL, HFILL }},

        { &hf_fcp_rsp_flags_sns_vld,
          { "SNS Vld", "fcp.rsp.flags.sns_vld",
            FT_BOOLEAN, 8, TFS(&fcp_rsp_flags_sns_vld_tfs), 0x02,
            NULL, HFILL }},

        { &hf_fcp_rsp_flags_res_vld,
          { "RES Vld", "fcp.rsp.flags.res_vld",
            FT_BOOLEAN, 8, TFS(&fcp_rsp_flags_res_vld_tfs), 0x01,
            NULL, HFILL }},

        { &hf_fcp_request_in,
          { "Request In", "fcp.request_in",
            FT_FRAMENUM, BASE_NONE, NULL, 0,
            "The frame number for the request", HFILL }},

        { &hf_fcp_response_in,
          { "Response In", "fcp.response_in",
            FT_FRAMENUM, BASE_NONE, NULL, 0,
            "The frame number of the response", HFILL }},

        { &hf_fcp_time,
          { "Time from FCP_CMND", "fcp.time",
            FT_RELATIVE_TIME, BASE_NONE, NULL, 0,
            "Time since the FCP_CMND frame", HFILL }},

        { &hf_fcp_els_op,
          {"Opcode", "fcp.els.op",
           FT_UINT8, BASE_HEX|BASE_EXT_STRING, &fc_els_proto_val_ext, 0x0,
           NULL, HFILL}},

        { &hf_fcp_srr_ox_id,
          {"OX_ID", "fcp.els.srr.ox_id",
           FT_UINT16, BASE_HEX, NULL, 0x0,
           NULL, HFILL}},

        { &hf_fcp_srr_rx_id,
          {"RX_ID", "fcp.els.srr.rx_id",
           FT_UINT16, BASE_HEX, NULL, 0x0,
           NULL, HFILL}},
    };

    /* Setup protocol subtree array */
    static int *ett[] = {
        &ett_fcp,
        &ett_fcp_taskmgmt,
        &ett_fcp_rsp_flags,
    };

    /* Register the protocol name and description */
    proto_fcp = proto_register_protocol("Fibre Channel Protocol for SCSI",
                                        "FCP", "fcp");

    /* Required function calls to register the header fields and subtrees used */
    proto_register_field_array(proto_fcp, hf, array_length(hf));
    proto_register_subtree_array(ett, array_length(ett));

    fcp_handle = register_dissector("fcp", dissect_fcp, proto_fcp);
}

void
proto_reg_handoff_fcp(void)
{
    dissector_add_uint("fc.ftype", FC_FTYPE_SCSI, fcp_handle);
}

/*
 * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 *
 * Local variables:
 * c-basic-offset: 4
 * tab-width: 8
 * indent-tabs-mode: nil
 * End:
 *
 * vi: set shiftwidth=4 tabstop=8 expandtab:
 * :indentSize=4:tabSize=8:noTabs=true:
 */