/* packet-isis-clv.c

 * Common CLV decode routines.

 *

 * Stuart Stanley <stuarts@mxmail.net>

 *

 * 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/expert.h>

#include "packet-isis.h"

#include "packet-isis-clv.h"

#include <epan/nlpid.h>

static const value_string algorithm_vals[] = {

    { 16, "hmac-md5" },

    { 20, "hmac-sha1" },

    { 28, "hmac-sha224" },

    { 32, "hmac-sha256" },

    { 48, "hmac-sha384" },

    { 64, "hmac-sha512" },

    { 0,  NULL }

};

static const value_string mt_id_vals[] = {

    { 0, "IPv4 Unicast" },

    { 1, "IPv4 In-Band Management" },

    { 2, "IPv6 Unicast" },

    { 3, "IPv4 Multicast" },

    { 4, "IPv6 Multicast" },

    { 5, "IPv6 In-Band Management" },

    { 4095, "Development, Experimental or Proprietary" },

    { 0,  NULL }

};

/*

 * Name: isis_dissect_area_address_clv()

 *

 * Description:

 *    Take an area address CLV and display it pieces.  An area address

 *    CLV is n, x byte hex strings.

 *

 * Input:

 *    tvbuff_t * : tvbuffer for packet data

 *    proto_tree * : protocol display tree to fill out.  May be NULL

 *    int : offset into packet data where we are.

 *    int : length of clv we are decoding

 *

 * Output:

 *    void, but we will add to proto tree if !NULL.

 */

void

isis_dissect_area_address_clv(proto_tree *tree, packet_info* pinfo, tvbuff_t *tvb,

        expert_field* expert, int hf_area, int offset, int length)

{

    int        arealen,area_idx;

    while ( length > 0 ) {

        arealen = tvb_get_uint8(tvb, offset);

        length--;

        if (length<=0) {

            proto_tree_add_expert_format(tree, pinfo, expert, tvb, offset, -1,

                "short address (no length for payload)");

            return;

        }

        if ( arealen > length) {

            proto_tree_add_expert_format(tree, pinfo, expert, tvb, offset, -1,

                "short address, packet says %d, we have %d left",

                arealen, length );

            return;

        }

        if ( tree ) {

            proto_item *ti;

            ti = proto_tree_add_bytes_format( tree, hf_area, tvb, offset, arealen + 1,

                NULL, "Area address (%d): ", arealen );

            /*

             * Lets turn the area address into "standard"

             * xx.xxxx.xxxx.xxxx.xxxx.xxxx.xxxx format string.

             * this is a private routine as the print_nsap_net in

             * epan/osi_utils.c is incomplete and we need only

             * a subset - actually some nice placing of dots ....

             */

            for (area_idx = 0; area_idx < arealen; area_idx++) {

                proto_item_append_text(ti, "%02x",

                    tvb_get_uint8(tvb, offset+area_idx+1));

                if (((area_idx & 1) == 0) &&

                    (area_idx + 1 < arealen)) {

                    proto_item_append_text(ti, ".");

                }

            }

        }

        offset += arealen + 1;

        length -= arealen;    /* length already adjusted for len fld*/

    }

}

/*

 * Name: isis_dissect_instance_identifier_clv()

 *

 *

 * Input:

 *    tvbuff_t * : tvbuffer for packet data

 *    proto_tree * : protocol display tree to fill out.  May be NULL

 *    int : offset into packet data where we are.

 *    int : length of clv we are decoding

 *

 * Output:

 *    void, but we will add to proto tree if !NULL.

 */

void

isis_dissect_instance_identifier_clv(proto_tree *tree, packet_info* pinfo, tvbuff_t *tvb,

        expert_field* expert, int hf_iid, int hf_supported_itid, int offset, int length)

{

    length--;

    if (length<=0) {

        proto_tree_add_expert_format(tree, pinfo, expert, tvb, offset, -1,

            "short address (no length for payload)");

        return;

    }

    proto_tree_add_item(tree, hf_iid, tvb, offset, 2, ENC_BIG_ENDIAN);

    offset += 2;

    length -= 2;

    while ( length > 0 ) {

        proto_tree_add_item(tree, hf_supported_itid, tvb, offset, 2, ENC_BIG_ENDIAN);

        offset += 2;

        length -= 2;

    }

}

/*

 * Name: isis_dissect_authentication_clv()

 *

 * Description:

 *    Take apart the CLV that hold authentication information.  This

 *    is currently 1 octet auth type.

 *      the two defined authentication types

 *      are 1 for a clear text password,

 *           54 for a HMAC-MD5 digest and

 *           3 for CRYPTO_AUTH (rfc5310)

 *

 * Input:

 *    tvbuff_t * : tvbuffer for packet data

 *    proto_tree * : protocol display tree to fill out.  May be NULL

 *    int : offset into packet data where we are.

 *    int : length of clv we are decoding

 *

 * Output:

 *    void, but we will add to proto tree if !NULL.

 */

void

isis_dissect_authentication_clv(proto_tree *tree, packet_info* pinfo, tvbuff_t *tvb,

        int hf_auth_bytes, int hf_key_id, expert_field* auth_expert, int offset, int length)

{

    unsigned char pw_type;

    int auth_unsupported;

    const char *algorithm = NULL;

    if ( length <= 0 ) {

        return;

    }

    pw_type = tvb_get_uint8(tvb, offset);

    offset += 1;

    length--;

    auth_unsupported = false;

    switch (pw_type) {

    case 1:

        if ( length > 0 ) {

            proto_tree_add_bytes_format( tree, hf_auth_bytes, tvb, offset, length,

                NULL, "clear text (1), password (length %d) = %s", length, tvb_format_text(pinfo->pool, tvb, offset, length));

        } else {

            proto_tree_add_bytes_format( tree, hf_auth_bytes, tvb, offset, length,

                NULL, "clear text (1), no clear-text password found!!!");

        }

        break;

    case 54:

        if ( length == 16 ) {

            proto_tree_add_bytes_format( tree, hf_auth_bytes, tvb, offset, length,

                NULL, "hmac-md5 (54), message digest (length %d) = %s", length, tvb_bytes_to_str(pinfo->pool, tvb, offset, length));

        } else {

            proto_tree_add_bytes_format( tree, hf_auth_bytes, tvb, offset, length,

                NULL, "hmac-md5 (54), illegal hmac-md5 digest format (must be 16 bytes)");

        }

        break;

    case 3:

        proto_tree_add_item(tree, hf_key_id, tvb, offset, 2, ENC_BIG_ENDIAN);

        offset += 2;

        length -= 2;

        algorithm = try_val_to_str(length, algorithm_vals);

        if ( algorithm ) {

            proto_tree_add_bytes_format( tree, hf_auth_bytes, tvb, offset, length,

                NULL, "CRYPTO_AUTH %s (3), message digest (length %d) = %s", algorithm,

                length, tvb_bytes_to_str(pinfo->pool, tvb, offset, length));

        } else {

            proto_tree_add_bytes_format( tree, hf_auth_bytes, tvb, offset, length,

                NULL, "CRYPTO_AUTH (3) illegal message digest format");

        }

        break;

    default:

        proto_tree_add_bytes_format( tree, hf_auth_bytes, tvb, offset, length,

                NULL, "type 0x%02x (0x%02x)", pw_type, length);

        auth_unsupported=true;

        break;

    }

    if ( auth_unsupported ) {

        proto_tree_add_expert(tree, pinfo, auth_expert, tvb, offset, -1);

    }

}

/*

 * Name: isis_dissect_hostname_clv()

 *

 * Description:

 *      dump the hostname information found in TLV 137

 *      pls note that the hostname is not null terminated

 *

 * Input:

 *      tvbuff_t * : tvbuffer for packet data

 *      proto_tree * : protocol display tree to fill out.  May be NULL

 *      int : offset into packet data where we are.

 *      int : length of clv we are decoding

 *      int : tree id to use for proto tree.

 *

 * Output:

 *      void, but we will add to proto tree if !NULL.

 */

void

isis_dissect_hostname_clv(tvbuff_t *tvb, proto_tree *tree, int offset,

    int length, int tree_id)

{

    proto_item* ti = proto_tree_add_item( tree, tree_id, tvb, offset, length, ENC_ASCII|ENC_NA);

    if ( length == 0 ) {

        proto_item_append_text(ti, "--none--" );

    }

}

void

isis_dissect_mt_clv(tvbuff_t *tvb, packet_info* pinfo, proto_tree *tree, int offset, int length,

    int tree_id, expert_field* mtid_expert)

{

    uint16_t mt_block;

    const char *mt_desc;

    while (length>0) {

        /* length can only be a multiple of 2, otherwise there is

           something broken -> so decode down until length is 1 */

        if (length!=1) {

        /* fetch two bytes */

        mt_block=tvb_get_ntohs(tvb, offset);

        mt_desc = val_to_str_const(mt_block&0x0fff, mt_id_vals, "Unknown");

        proto_tree_add_uint_format ( tree, tree_id, tvb, offset, 2,

            mt_block,

            "%s Topology (0x%03x)%s%s",

                      mt_desc,

                      mt_block&0xfff,

                      (mt_block&0x8000) ? ", Overload bit set" : "",

                      (mt_block&0x4000) ? ", ATT bit set" : "" );

        } else {

        proto_tree_add_expert( tree, pinfo, mtid_expert, tvb, offset, 1);

        break;

        }

        length -= 2;

        offset += 2;

    }

}

/*

 * Name: isis_dissect_ip_int_clv()

 *

 * Description:

 *    Take apart the CLV that lists all the IP interfaces.  The

 *    meaning of which is slightly different for the different base packet

 *    types, but the display is not different.  What we have is n ip

 *    addresses, plain and simple.

 *

 * Input:

 *    tvbuff_t * : tvbuffer for packet data

 *    proto_tree * : protocol display tree to fill out.  May be NULL

 *    int : offset into packet data where we are.

 *    int : length of clv we are decoding

 *    int : tree id to use for proto tree.

 *

 * Output:

 *    void, but we will add to proto tree if !NULL.

 */

void

isis_dissect_ip_int_clv(proto_tree *tree, packet_info* pinfo, tvbuff_t *tvb, expert_field* expert,

    int offset, int length, int tree_id)

{

    if ( length <= 0 ) {

        return;

    }

    while ( length > 0 ) {

        if ( length < 4 ) {

            proto_tree_add_expert_format(tree, pinfo, expert, tvb, offset, -1,

                "Short IP interface address (%d vs 4)",length );

            return;

        }

        if ( tree ) {

            proto_tree_add_item(tree, tree_id, tvb, offset, 4, ENC_BIG_ENDIAN);

        }

        offset += 4;

        length -= 4;

    }

}

/*

 * Name: isis_dissect_ipv6_int_clv()

 *

 * Description:

 *    Take apart the CLV that lists all the IPv6 interfaces.  The

 *    meaning of which is slightly different for the different base packet

 *    types, but the display is not different.  What we have is n ip

 *    addresses, plain and simple.

 *

 * Input:

 *    tvbuff_t * : tvbuffer for packet data

 *    proto_tree * : protocol display tree to fill out.  May be NULL

 *    int : offset into packet data where we are.

 *    int : length of clv we are decoding

 *    int : tree id to use for proto tree.

 *

 * Output:

 *    void, but we will add to proto tree if !NULL.

 */

void

isis_dissect_ipv6_int_clv(proto_tree *tree, packet_info* pinfo, tvbuff_t *tvb, expert_field* expert,

    int offset, int length, int tree_id)

{

    ws_in6_addr addr;

    if ( length <= 0 ) {

        return;

    }

    while ( length > 0 ) {

        if ( length < 16 ) {

            proto_tree_add_expert_format(tree, pinfo, expert, tvb, offset, -1,

                "Short IPv6 interface address (%d vs 16)",length );

            return;

        }

        tvb_get_ipv6(tvb, offset, &addr);

        if ( tree ) {

            proto_tree_add_ipv6(tree, tree_id, tvb, offset, 16, &addr);

        }

        offset += 16;

        length -= 16;

    }

}

/*

 * Name: isis_dissect_te_router_id_clv()

 *

 * Description:

 *      Display the Traffic Engineering Router ID TLV #134.

 *      This TLV is like the IP Interface TLV, except that

 *      only _one_ IP address is present

 *

 * Input:

 *      tvbuff_t * : tvbuffer for packet data

 *      proto_tree * : protocol display tree to fill out.  May be NULL

 *      int : offset into packet data where we are.

 *      int : length of clv we are decoding

 *      int : tree id to use for proto tree.

 *

 * Output:

 *      void, but we will add to proto tree if !NULL.

 */

void

isis_dissect_te_router_id_clv(proto_tree *tree, packet_info* pinfo, tvbuff_t *tvb, expert_field* expert,

    int offset, int length, int tree_id)

{

    if ( length <= 0 ) {

        return;

    }

    if ( length != 4 ) {

        proto_tree_add_expert_format(tree, pinfo, expert, tvb, offset, -1,

            "malformed Traffic Engineering Router ID (%d vs 4)",length );

        return;

    }

    proto_tree_add_item(tree, tree_id, tvb, offset, 4, ENC_BIG_ENDIAN);

}

/*

 * Name: isis_dissect_nlpid_clv()

 *

 * Description:

 *    Take apart a NLPID packet and display it.  The NLPID (for integrated

 *    ISIS, contains n network layer protocol IDs that the box supports.

 *    We max out at 256 entries.

 *

 * Input:

 *    tvbuff_t * : tvbuffer for packet data

 *    proto_tree * : protocol display tree to fill out.  May be NULL

 *    int : offset into packet data where we are.

 *    int : length of clv we are decoding

 *

 * Output:

 *    void, but we will add to proto tree if !NULL.

 */

#define PLURALIZE(n)  (((n) > 1) ? "s" : "")

void

isis_dissect_nlpid_clv(tvbuff_t *tvb, proto_tree *tree, int ett_nlpid, int hf_nlpid, int offset, int length)

{

    proto_tree *nlpid_tree;

    proto_item *ti;

    uint8_t nlpid;

    if (length <= 0) {

        proto_tree_add_subtree_format(tree, tvb, offset, 0, ett_nlpid, NULL, "No NLPIDs");

    } else {

        nlpid_tree = proto_tree_add_subtree_format(tree, tvb, offset, length, ett_nlpid, &ti, "NLPID%s: ", PLURALIZE(length));

        while (length-- > 0 ) {

            nlpid = tvb_get_uint8(tvb, offset);

            proto_item_append_text(ti, "%s (0x%02x)",

                   /* NLPID_IEEE_8021AQ conflicts with NLPID_SNDCF. In this context, we want the former. */

                   (nlpid == NLPID_IEEE_8021AQ ? "IEEE 802.1aq (SPB)" : val_to_str_const(nlpid, nlpid_vals, "Unknown")),

                   nlpid);

            if (length) {

                proto_item_append_text(ti, ", ");

            }

            proto_tree_add_uint(nlpid_tree, hf_nlpid, tvb, offset, 1, nlpid);

            offset++;

        }

    }

}

/*

 * Name: isis_dissect_clvs()

 *

 * Description:

 *    Dispatch routine to shred all the CLVs in a packet.  We just

 *    walk through the clv entries in the packet.  For each one, we

 *    search the passed in valid clv's for this protocol (opts) for

 *    a matching code.  If found, we add to the display tree and

 *    then call the dissector.  If it is not, we just post an

 *    "unknown" clv entry using the passed in unknown clv tree id.

 *

 * Input:

 *    tvbuff_t * : tvbuffer for packet data

 *    packet_info * : packet_info for dissection

 *    proto_tree * : protocol display tree to fill out.  May be NULL

 *    int : offset into packet data where we are.

 *    isis_clv_handle_t * : NULL dissector terminated array of codes

 *        and handlers (along with tree text and tree id's).

 *    expert_field * : expert info for short length

 *    isis_data_t * : data about the PDU from earlier headers

 *    int : unknown clv tree id

 *

 * Output:

 *    void, but we will add to proto tree if !NULL.

 */

void

isis_dissect_clvs(tvbuff_t *tvb, packet_info* pinfo, proto_tree *tree, int offset,

    const isis_clv_handle_t *opts, expert_field *expert_short_len, isis_data_t *isis,

    int unknown_tree_id _U_, int tree_type, int tree_length, expert_field *ei_unknown)

{

    unsigned len = isis->pdu_length - isis->header_length; /* length of CLV area */

    uint8_t code;

    uint8_t length;

    int q;

    proto_tree    *clv_tree;

    while ( len != 0 ) {

        code = tvb_get_uint8(tvb, offset);

        offset += 1;

        len -= 1;

        if (len == 0)

            break;

        length = tvb_get_uint8(tvb, offset);

        offset += 1;

        len -= 1;

        if (len == 0)

            break;

        if ( len < length ) {

            proto_tree_add_expert_format(tree, pinfo, expert_short_len, tvb, offset, -1,

                "Short CLV header (%d vs %d)",

                length, len );

            return;

        }

        q = 0;

        while ((opts[q].dissect != NULL )&&( opts[q].optcode != code )){

            q++;

        }

        if ( opts[q].dissect ) {

            /* adjust by 2 for code/len octets */

            clv_tree = proto_tree_add_subtree_format(tree, tvb, offset - 2,

                    length + 2, *opts[q].tree_id, NULL, "%s (t=%u, l=%u)",

                    opts[q].tree_text, opts[q].optcode, length);

            proto_tree_add_item(clv_tree, tree_type, tvb, offset - 2, 1, ENC_BIG_ENDIAN);

            proto_tree_add_item(clv_tree, tree_length, tvb, offset - 1, 1, ENC_BIG_ENDIAN);

            opts[q].dissect(tvb, pinfo, clv_tree, offset, isis, length);

        } else {

            clv_tree = proto_tree_add_subtree_format(tree, tvb, offset - 2,

                    length + 2, unknown_tree_id, NULL, "Unknown code (t=%u, l=%u)",

                    code, length);

            proto_tree_add_item(clv_tree, tree_type, tvb, offset - 2, 1, ENC_BIG_ENDIAN);

            proto_tree_add_item(clv_tree, tree_length, tvb, offset - 1, 1, ENC_BIG_ENDIAN);

            proto_tree_add_expert_format(clv_tree, pinfo, ei_unknown, tvb, offset, length, "Dissector for IS-IS CLV (%d)"

              " code not implemented, Contact Wireshark developers if you want this supported", code);

        }

        offset += length;

        len -= length;

    }

}

/*

 * 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:

 */