/* packet-lmi.c

 * Routines for Frame Relay Local Management Interface (LMI) disassembly

 * Copyright 2001, Jeffrey C. Foster <jfoste@woodward.com>

 *

 * Wireshark - Network traffic analyzer

 * By Gerald Combs <gerald@wireshark.org>

 * Copyright 1998

 *

 * SPDX-License-Identifier: GPL-2.0-or-later

 *

 * ToDo:

 *

 * References:

 *

 * http://www.techfest.com/networking/wan/frrel.htm

 * http://rfc.nop.hu/frf/frf1_2.pdf

 * http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/frame.htm#xtocid18

 * http://www.net.aapt.com.au/techref/lmimess.htm

 * http://www.raleigh.ibm.com:80/cgi-bin/bookmgr/BOOKS/EZ305800/1.2.4.4

 */

#include "config.h"

#include <epan/packet.h>

#include "packet-osi.h"

void proto_register_lmi(void);

void proto_reg_handoff_lmi(void);

static dissector_handle_t lmi_handle;

static int proto_lmi;

static int hf_lmi_call_ref;

static int hf_lmi_msg_type;

static int hf_lmi_inf_ele;

static int hf_lmi_inf_len;

static int hf_lmi_rcd_type;

static int hf_lmi_send_seq;

static int hf_lmi_recv_seq;

static int hf_lmi_dlci_high;

static int hf_lmi_dlci_low;

static int hf_lmi_new;

static int hf_lmi_act;

static int ett_lmi;

static int ett_lmi_ele;

#ifdef _OLD_

/*

 * Bits in the address field.

 */

#define LMI_CMD 0xf000    /* LMI Command */

#define LMI_SEQ 0x0fff    /* LMI Sequence number */

#endif

static const value_string msg_type_str[] = {

    {0x75, "Status Enquiry"},

    {0x7D, "Status"},

    { 0,   NULL }

};

static const value_string element_type_str[] = {

    /*** These are the ANSI values ***/

    {0x01, "Report"},

    {0x03, "Keep Alive"},

    {0x07, "PVC Status"},

    /*** These are the ITU values ***/

    {0x51, "Report"},

    {0x53, "Keep Alive"},

    //{0x07, "PVC Status"},

    {0,       NULL }

};

static const value_string record_type_str[] = {

    {0x00, "Full Status"},

    {0x01, "Link Integrity Verification Only"},

    {0x02, "Single PVC"},

    {0,    NULL }

};

static const value_string pvc_status_new_str[] = {

    {0x00, "PVC already present"},

    {0x01, "PVC is new"},

    {0,    NULL }

};

static const value_string pvc_status_act_str[] = {

    {0x00, "PVC is Inactive"},

    {0x01, "PVC is Active"},

    {0,    NULL }

};

static void

dissect_lmi_report_type(tvbuff_t *tvb, int offset, proto_tree *tree)

{

    proto_tree_add_item(tree, hf_lmi_rcd_type, tvb, offset, 1, ENC_NA);

}

static void

dissect_lmi_link_int(tvbuff_t *tvb, int offset, proto_tree *tree)

{

    proto_tree_add_item(tree, hf_lmi_send_seq, tvb, offset, 1, ENC_NA);

    ++offset;

    proto_tree_add_item(tree, hf_lmi_recv_seq, tvb, offset, 1, ENC_NA);

}

static void

dissect_lmi_pvc_status(tvbuff_t *tvb, int offset, proto_tree *tree)

{

    proto_tree_add_item(tree, hf_lmi_dlci_high, tvb, offset, 1, ENC_NA);

    ++offset;

    proto_tree_add_item(tree, hf_lmi_dlci_low, tvb, offset, 1, ENC_NA);

    ++offset;

    proto_tree_add_item(tree, hf_lmi_new, tvb, offset, 1, ENC_NA);

    proto_tree_add_item(tree, hf_lmi_act, tvb, offset, 1, ENC_NA);

}

static int

dissect_lmi(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)

{

    proto_tree    *lmi_tree, *lmi_subtree;

    proto_item    *ti;

    int           offset = 2, len;

    uint32_t       msg_type;

    uint8_t       ele_id;

    col_set_str(pinfo->cinfo, COL_PROTOCOL, "LMI");

    col_clear(pinfo->cinfo, COL_INFO);

    ti = proto_tree_add_item(tree, proto_lmi, tvb, 0, 3, ENC_NA);

    lmi_tree = proto_item_add_subtree(ti, ett_lmi_ele);

    proto_tree_add_item(lmi_tree, hf_lmi_call_ref, tvb, 0, 1, ENC_BIG_ENDIAN);

    proto_tree_add_item_ret_uint(lmi_tree, hf_lmi_msg_type, tvb, 1, 1, ENC_BIG_ENDIAN, &msg_type);

    col_add_str(pinfo->cinfo, COL_INFO,

        val_to_str(pinfo->pool, msg_type, msg_type_str, "Unknown message type (0x%02x)"));

    /* Display the LMI elements */

    while (tvb_reported_length_remaining(tvb, offset) > 0) {

        ele_id = tvb_get_uint8( tvb, offset);

        len =  tvb_get_uint8( tvb, offset + 1);

        lmi_subtree = proto_tree_add_subtree_format(lmi_tree, tvb, offset, len + 2,

                ett_lmi_ele, NULL, "Information Element: %s",

                val_to_str(pinfo->pool, ele_id, element_type_str, "Unknown (%u)"));

        proto_tree_add_uint(lmi_subtree, hf_lmi_inf_ele, tvb, offset, 1, ele_id);

        ++offset;

        proto_tree_add_uint(lmi_subtree, hf_lmi_inf_len, tvb, offset, 1, len);

        ++offset;

        switch(ele_id)

        {

        case 1:

        case 51:

            dissect_lmi_report_type( tvb, offset, lmi_subtree);

            break;

        case 3:

        case 53:

            dissect_lmi_link_int( tvb, offset, lmi_subtree);

            break;

        case 7:

        case 57:

            dissect_lmi_pvc_status( tvb, offset, lmi_subtree);

            break;

        }

        offset += len;

    }

    return tvb_captured_length(tvb);

}

void

proto_register_lmi(void)

{

    static hf_register_info hf[] = {

        { &hf_lmi_call_ref,

            { "Call reference", "lmi.cmd", FT_UINT8, BASE_HEX, NULL, 0,

                NULL, HFILL }},

        { &hf_lmi_msg_type,

            { "Message Type", "lmi.msg_type", FT_UINT8, BASE_HEX, VALS(msg_type_str), 0,

                NULL, HFILL }},

        { &hf_lmi_inf_ele,

            { "Type", "lmi.inf_ele_type", FT_UINT8, BASE_DEC, VALS(element_type_str), 0,

                "Information Element Type", HFILL }},

        { &hf_lmi_inf_len,

            { "Length", "lmi.inf_ele_len", FT_UINT8, BASE_DEC, NULL, 0,

                "Information Element Length", HFILL }},

        { &hf_lmi_rcd_type,

            { "Record Type", "lmi.ele_rcd_type", FT_UINT8, BASE_DEC, VALS(record_type_str), 0,

                NULL, HFILL }},

        { &hf_lmi_send_seq,

            { "Send Seq", "lmi.send_seq", FT_UINT8, BASE_DEC, NULL, 0,

                "Send Sequence", HFILL }},

        { &hf_lmi_recv_seq,

            { "Recv Seq", "lmi.recv_seq", FT_UINT8, BASE_DEC, NULL, 0,

                "Receive Sequence", HFILL }},

        { &hf_lmi_dlci_high,

            { "DLCI High", "lmi.dlci_hi", FT_UINT8, BASE_DEC, NULL, 0x3f,

                "DLCI High bits", HFILL }},

        { &hf_lmi_dlci_low,

            { "DLCI Low", "lmi.dlci_low", FT_UINT8, BASE_DEC, NULL, 0x78,

                "DLCI Low bits", HFILL }},

        { &hf_lmi_new,

            { "DLCI New", "lmi.dlci_new", FT_UINT8, BASE_DEC, VALS(pvc_status_new_str), 0x08,

                "DLCI New Flag", HFILL }},

        { &hf_lmi_act,

            { "DLCI Active","lmi.dlci_act", FT_UINT8, BASE_DEC, VALS(pvc_status_act_str), 0x02,

                "DLCI Active Flag", HFILL }},

    };

    static int *ett[] = {

        &ett_lmi,

        &ett_lmi_ele,

    };

    proto_lmi = proto_register_protocol ("Local Management Interface", "LMI", "lmi");

    proto_register_field_array (proto_lmi, hf, array_length(hf));

    proto_register_subtree_array(ett, array_length(ett));

    lmi_handle = register_dissector("lmi", dissect_lmi, proto_lmi);

}

void

proto_reg_handoff_lmi(void)

{

    dissector_add_uint("fr.nlpid", NLPID_LMI, lmi_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:

 */