/* packet-wsmp.c

 * Routines for WAVE Short Message  dissection (WSMP)

 * Copyright 2013, Savari Networks (http://www.savarinetworks.com) (email: smooney@savarinetworks.com)

 *  Based on packet-wsmp.c implemented by

 *  Arada Systems (http://www.aradasystems.com) (email: siva@aradasystems.com)

 *

 * Wireshark - Network traffic analyzer

 * By Gerald Combs <gerald@wireshark.org>

 * Copyright 1998 Gerald Combs

 *

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

 * Ref IEEE 1609.3

 */

#include "config.h"

#include <epan/packet.h>

#include <epan/etypes.h>

#include <epan/expert.h>

#include <epan/tfs.h>

#include <wsutil/array.h>

#include "packet-ieee1609dot2.h"

/* elemenID Types */

#define TRANSMITPW 0x04

#define CHANNUM    0x0F

#define DATARATE   0x10

#define WSMP       0x80

#define WSMP_S     0x81

#define WSMP_I     0x82

void proto_register_wsmp(void);

void proto_reg_handoff_wsmp(void);

static dissector_handle_t wsmp_handle;

static const value_string wsmp_elemenid_names[] = {

    { 0x80, "WSMP" },

    { 0x81, "WSMP-S" },

    { 0x82, "WSMP-I" },

    { 0, NULL }

};

/* Dissector table to be passed to IEEE 1609.2 dissector */

static dissector_table_t ieee1609dot2_psid_table;

/* Initialize the protocol and registered fields */

static int proto_wsmp;

static int hf_wsmp_version;

static int hf_wsmp_var_len_det;

static int hf_wsmp_psid;

static int hf_wsmp_rate;

static int hf_wsmp_channel;

static int hf_wsmp_txpower;

static int hf_wsmp_WAVEid;

static int hf_wsmp_wsmlength;

static int hf_wsmp_WSMP_S_data;

static int hf_wsmp_subtype;

static int hf_wsmp_N_header_opt_ind;

static int hf_wsmp_version_v3;

static int hf_wsmp_no_elements;

static int hf_wsmp_wave_ie;

static int hf_wsmp_wave_ie_len;

static int hf_wsmp_wave_ie_data;

static int hf_wsmp_tpid;

/* Initialize the subtree pointers */

static int ett_wsmp;

static int ett_wsmdata;

static int ett_wsmp_n_hdr;

static int ett_wsmp_t_hdr;

static int ett_wsmp_ie_ext;

static int ett_wsmp_ie;

static expert_field ei_wsmp_length_field_err;

static expert_field ei_wsmp_psid_invalid;

static const value_string wsmp_subtype_vals[] = {

    { 0x0, "Null-networking protocol" },

    { 0x1, "ITS station-internal forwarding" },

    { 0x2, "N-hop forwarding" },

    { 0x3, "Enables the features of GeoNetworking" },

    { 0, NULL }

};

static const value_string wsmp_wave_information_elements_vals[] = {

    { 0, "Reserved" },

    { 1, "Reserved" },

    { 2, "Reserved" },

    { 3, "Reserved" },

    { 4, "Transmit Power Used" },                   /* WSMP - N - Header 8.3.4.4 */

    { 5, "2D Location" },                           /* WSA header 8.2.2.6 */

    { 6, "3D Location" },                           /* WSA header 8.2.2.6 */

    { 7, "Advertiser Identifier" },                 /* WSA header 8.2.2.6 */

    { 8, "Provider Service Context" },              /* WSA Service Info 8.2.3.5 */

    { 9, "IPv6 Address" },                          /* WSA Service Info 8.2.3.5 */

    { 10, "Service Por" },                          /* WSA Service Info 8.2.3.5 */

    { 11, "Provider MAC Address" },                 /* WSA Service Info 8.2.3.5 */

    { 12, "EDCA Parameter Set" },                   /* WSA Channel Info 8.2.4.8 */

    { 13, "Secondary DNS" },                        /* WSA WRA 8.2.5.7 */

    { 14, "Gateway MAC Address" },                  /* WSA WRA 8.2.5.7 */

    { 15, "Channel Number" },                       /* WSMP - N - Header 8.3.4.2 */

    { 16, "Data Rate" },                            /* WSMP - N - Header 8.3.4.3 */

    { 17, "Repeat Rate" },                          /* WSA header 8.2.2.6 */

    { 18, "Reserved" },

    { 19, "RCPI Threshold" },                       /* WSA Service Info 8.2.3.5 */

    { 20, "WSA Count Threshold" },                  /* WSA Service Info 8.2.3.5 */

    { 21, "Channel Access" },                       /* WSA Channel Info 8.2.4.8 */

    { 22, "WSA Count Threshold Interval" },         /* WSA Service Info 8.2.3.5 */

    { 23, "Channel Load" },                         /* WSMP-N-Header 8.3.4.5 */

    { 0, NULL }

};

static const value_string wsmp_tpid_vals[] = {

    { 0, "The Address Info field contains a PSID and a WAVE Information Element Extension field is not present" },

    { 1, "The Address Info field contains a PSID and a WAVE Information Element Extension field is present" },

    { 2, "The Address Info field contains source and destination ITS port numbers and a WAVE Information Element Extension field is not present" },

    { 3, "The Address Info field contains source and destination ITS port numbers and a WAVE Information Element Extension field is present" },

    { 4, "LPP mode and a WAVE Information Element Extension field is not present" },

    { 5, "LPP mode and a WAVE Information Element Extension field is present" },

    { 0, NULL }

};

/*

4.1.2 P-encoding of PSIDs

    This standard defines a compact encoding for PSID referred to as p-encoding. Octets are numbered from the

    left starting at zero (Octet 0). The length of the PSID is indicated by Octet 0, where the position of the first

    zero-value bit in descending order of bit significance in the octet indicates the length in octets of the p?encoded

    PSID. Using p-encoding, a binary "0" in the most-significant bit indicates a one-octet PSID; a binary "10"

    in the two most-significant bits indicates a two-octet PSID; a binary "110" in the three most-significant bits

    indicates a three-octet PSID; and a binary "1110" in the four most-significant bits indicates a four-octet PSID.

*/

static int

dissect_wsmp_psid(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree, int offset, uint32_t *psid)

{

    uint8_t oct;

    uint32_t psidLen = 0;

    oct = tvb_get_uint8(tvb, offset);

    *psid = 0;

    if ((oct & 0xF0) == 0xF0) {

        proto_tree_add_expert(tree, pinfo, &ei_wsmp_psid_invalid, tvb, offset, 1);

        return offset + 1;

    } else if ((oct & 0xF0) == 0xE0) {

        psidLen = 4;

    } else if ((oct & 0xE0) == 0xC0) {

        psidLen = 3;

    } else if ((oct & 0xC0) == 0x80) {

        psidLen = 2;

    } else if ((oct & 0x80) == 0x00) {

        psidLen = 1;

    }

    if (psidLen == 1)

        *psid = oct;

    else if (psidLen == 2)

        *psid = (tvb_get_ntohs(tvb, offset) & ~0x8000) + 0x80;

    else if (psidLen == 3)

        *psid = (tvb_get_ntoh24(tvb, offset) & ~0xc00000) + 0x4080;

    else if (psidLen == 4)

        *psid = (tvb_get_ntohl(tvb, offset) & ~0xe0000000) + 0x204080;

    proto_tree_add_bits_item(tree, hf_wsmp_var_len_det, tvb, offset << 3, psidLen, ENC_NA);

    proto_tree_add_uint_bits_format_value(tree, hf_wsmp_psid, tvb, (offset << 3) + psidLen,

            (psidLen << 3) - psidLen,*psid,ENC_BIG_ENDIAN,"%s(%u)", val64_to_str_const(*psid, ieee1609dot2_Psid_vals, "Unknown"), *psid);

    offset += psidLen;

    return offset;

}

/* 8.1.3 Length and Count field encoding*/

static int

dissect_wsmp_length_and_count(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int offset, int hf_id, uint16_t* value)

{

    uint8_t oct, len;

    uint16_t val;

    /* For values in the range of 0 through 127, Length and Count values

     * are represented in a single-octet encoded as an unsigned integer. For values in the range 128 through 16

     * 383, values are represented as two octets encoded as follows. If the most significant bit of the field is 0b0,

     * then this indicates a one-octet Length or Count field. If the two most significant bits of the field are 0b10,

     * the Length or Count field is a two-octet field, with the remaining 14 bits representing the value encoded as

     * an unsigned integer.*/

    oct = tvb_get_uint8(tvb, offset);

    if ((oct & 0x80) == 0x80) {

        if ((oct & 0xc0) == 0x80) {

            /* Two bytes */

            val = tvb_get_ntohs(tvb, offset) & 0x3fff;

            len = 2;

        } else {

            /* Error */

            proto_tree_add_expert(tree, pinfo, &ei_wsmp_length_field_err, tvb, offset, 1);

            val = tvb_get_ntohs(tvb, offset) & 0x3fff;

            len = 2;

        }

    }else{

        /* One byte */

        val = oct;

        len = 1;

    }

    proto_tree_add_uint(tree, hf_id, tvb, offset, len, val);

    offset += len;

    if (value){

        *value = val;

    }

    return offset;

}

static int

dissect_wsmp_v3(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, uint8_t oct)

{

    proto_tree *sub_tree, *n_tree, *t_tree, *data_tree;

    proto_item *item, *n_tree_item, *t_tree_item;

    int offset = 0, ie_start, len_to_set;

    uint8_t header_opt_ind = (oct & 0x08) >> 3;

    uint8_t ie;

    uint16_t count, ie_len, wsm_len;

    uint32_t tpid, psid = 0;

    static int * const flags[] = {

        &hf_wsmp_subtype,

        &hf_wsmp_N_header_opt_ind,

        &hf_wsmp_version_v3,

        NULL

    };

    /* 8.3.2 WSMP Network Header (WSMP-N-Header) */

    n_tree = proto_tree_add_subtree(tree, tvb, offset, -1, ett_wsmp_n_hdr, &n_tree_item, "WSMP-N-Header");

    /* In Version 3

    * B7     B4          B3            B2   B0     | Variable                            | 1 octet

    * Subtype    |WSMP-NHeader      | WSMP Version |  WAVE Information Element Extension | TPID

    *            | Option Indicator |              |                                     |

    */

    proto_tree_add_bitmask_list(n_tree, tvb, offset, 1, flags, ENC_BIG_ENDIAN);

    offset++;

    /* WAVE Information Element Extension */

    if (header_opt_ind) {

        sub_tree = proto_tree_add_subtree(n_tree, tvb, offset, -1, ett_wsmp_ie_ext, &item, "WAVE Information Element Extension");

        /* Figure 14 WAVE Information Element Extension */

        /* 8.1.3 Length and Count field encoding*/

        /* Count( Number of WAVE Information Elements )*/

        offset = dissect_wsmp_length_and_count(tvb, pinfo, sub_tree, offset, hf_wsmp_no_elements, &count);

        while (count) {

            proto_tree* ie_tree;

            ie_start = offset;

            /* WAVE Element ID 1 octet*/

            ie = tvb_get_uint8(tvb, offset);

            ie_tree = proto_tree_add_subtree_format(sub_tree, tvb, offset, -1, ett_wsmp_ie, &item, "%s",

                val_to_str_const(ie, wsmp_wave_information_elements_vals, "Unknown"));

            proto_tree_add_item(ie_tree, hf_wsmp_wave_ie, tvb, offset, 1, ENC_BIG_ENDIAN);

            offset++;

            /* Length */

            offset = dissect_wsmp_length_and_count(tvb, pinfo, ie_tree, offset, hf_wsmp_wave_ie_len, &ie_len);

            proto_tree_add_item(ie_tree, hf_wsmp_wave_ie_data, tvb, offset, ie_len, ENC_NA);

            offset += ie_len;

            len_to_set = offset - ie_start;

            proto_item_set_len(item, len_to_set);

            count--;

        }

    }

    /* TPID */

    proto_tree_add_item_ret_uint(n_tree, hf_wsmp_tpid, tvb, offset, 1, ENC_BIG_ENDIAN, &tpid);

    offset++;

    proto_item_set_end(n_tree_item, tvb, offset);

    /* WSMP-T-Header */

    t_tree = proto_tree_add_subtree(tree, tvb, offset, -1, ett_wsmp_t_hdr, &t_tree_item, "WSMP-T-Header");

    switch (tpid) {

        case 0:

            /* The Address Info field contains a PSID and a WAVE Information Element Extension field is not present.*/

            offset = dissect_wsmp_psid(tvb, pinfo, t_tree, offset, &psid);

            break;

        default:

            break;

    }

    /* WSM Length */

    offset = dissect_wsmp_length_and_count(tvb, pinfo, t_tree, offset, hf_wsmp_wave_ie_len, &wsm_len);

    proto_item_set_end(t_tree_item, tvb, offset);

    /* WSM Data */

    data_tree = proto_tree_add_subtree(tree, tvb, offset, wsm_len, ett_wsmdata, NULL, "Wave Short Message");

    if(NULL != ieee1609dot2_psid_table){

        ieee1609dot2_set_next_default_psid(pinfo, psid);

        tvbuff_t* tvb_new = tvb_new_subset_remaining(tvb, offset);

        dissector_try_uint(ieee1609dot2_psid_table,

                           psid,

                           tvb_new,

                           pinfo,

                           data_tree);

    }

    return tvb_captured_length(tvb);

}

static int

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

{

    /* Set up structures needed to add the protocol subtree and manage it */

    proto_item *ti;

    proto_tree *wsmp_tree, *wsmdata_tree;

    tvbuff_t   *wsmdata_tvb;

    uint16_t    wsmlength, offset = 0;

    uint32_t    psid, supLen;

    uint8_t     elemenId, elemenLen, msb, oct, version;

    /* Make entries in Protocol column and Info column on summary display */

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

    col_set_str(pinfo->cinfo, COL_INFO, "WAVE Short Message Protocol IEEE P1609.3");

    /* create display subtree for the protocol */

    ti = proto_tree_add_item(tree, proto_wsmp, tvb, 0, -1, ENC_NA);

    wsmp_tree = proto_item_add_subtree(ti, ett_wsmp);

    /* In Version 3

     * B7     B4          B3            B2   B0

     * Subtype    |WSMP-NHeader      | WSMP Version

     *            | Option Indicator

     */

    oct = tvb_get_uint8(tvb, offset);

    version = oct & 0x07;

    if (version == 3) {

        /* Version 3 */

        return dissect_wsmp_v3(tvb, pinfo, wsmp_tree, oct);

    }

    proto_tree_add_item(wsmp_tree, hf_wsmp_version, tvb, offset, 1, ENC_BIG_ENDIAN);

    offset++;

    offset = dissect_wsmp_psid(tvb, pinfo, wsmp_tree, offset, &psid);

    /* TLV decoder that does not display the T and L elements */

    elemenId = tvb_get_uint8(tvb, offset);

    while ((elemenId != WSMP) && (elemenId != WSMP_S) && (elemenId != WSMP_I))

    {

        offset++;

        if (elemenId == CHANNUM)

        {

            elemenLen = tvb_get_uint8(tvb, offset);

            offset++;

            proto_tree_add_item(wsmp_tree,

                                hf_wsmp_channel, tvb, offset, elemenLen, ENC_BIG_ENDIAN);

            offset += elemenLen;

        }

        else if (elemenId == DATARATE)

        {

            elemenLen = tvb_get_uint8(tvb, offset);

            offset++;

            proto_tree_add_item(wsmp_tree,

                                hf_wsmp_rate, tvb, offset, elemenLen, ENC_BIG_ENDIAN);

            offset += elemenLen;

        }

        else if (elemenId == TRANSMITPW)

        {

            elemenLen = tvb_get_uint8(tvb, offset);

            offset++;

            proto_tree_add_item(wsmp_tree,

                                hf_wsmp_txpower, tvb, offset, elemenLen, ENC_BIG_ENDIAN);

            offset += elemenLen;

        }

        elemenId  = tvb_get_uint8(tvb, offset);

    }

    proto_tree_add_item(wsmp_tree,

                        hf_wsmp_WAVEid, tvb, offset, 1, ENC_BIG_ENDIAN);

    offset++;

    wsmlength = tvb_get_ntohs( tvb, offset);

    proto_tree_add_item(wsmp_tree,

                        hf_wsmp_wsmlength, tvb, offset, 2, ENC_BIG_ENDIAN);

    offset += 2;

    if (elemenId == WSMP_S)

    {

        msb    = 1;

        supLen = 0;

        while (msb)

        {

            msb = tvb_get_uint8(tvb, offset + supLen);

            msb = msb & 0x80;

            supLen++;

        }

        proto_tree_add_item(wsmp_tree,

                            hf_wsmp_WSMP_S_data, tvb, offset, supLen, ENC_BIG_ENDIAN);

        wsmlength -= supLen;

        offset    += supLen;

    }

    wsmdata_tree = proto_tree_add_subtree(wsmp_tree, tvb, offset, wsmlength,

                                        ett_wsmdata, NULL, "Wave Short Message");

    wsmdata_tvb  = tvb_new_subset_length(tvb, offset, wsmlength);

    /* TODO: Branch on the application context and display accordingly

     * Default: call the data dissector

     */

    if (psid == 0x4070)

    {

        call_data_dissector(wsmdata_tvb, pinfo, wsmdata_tree);

    }

    return tvb_captured_length(tvb);

}

void

proto_register_wsmp(void)

{

    static hf_register_info hf[] = {

        { &hf_wsmp_version,

          { "Version", "wsmp.version", FT_UINT8, BASE_DEC, NULL, 0x0,

            NULL, HFILL }},

        { &hf_wsmp_var_len_det,

          { "Length", "wsmp.len.det",

            FT_UINT8, BASE_HEX, NULL, 0x0,

            NULL, HFILL }},

        { &hf_wsmp_psid,

          { "PSID", "wsmp.psid", FT_UINT32, BASE_HEX, NULL, 0x0,

            NULL, HFILL }},

        { &hf_wsmp_channel,

          { "Channel", "wsmp.channel", FT_UINT8, BASE_DEC, NULL, 0x0,

            NULL, HFILL }},

        { &hf_wsmp_rate,

          { "Data Rate", "wsmp.rate", FT_UINT8, BASE_DEC, NULL, 0x0,

            NULL, HFILL }},

        { &hf_wsmp_txpower,

          { "Transmit Power", "wsmp.txpower", FT_UINT8, BASE_DEC, NULL, 0x0,

            NULL, HFILL }},

        { &hf_wsmp_WAVEid,

          { "WAVE element id", "wsmp.WAVEid", FT_UINT8, BASE_DEC, VALS(wsmp_elemenid_names), 0x0,

            NULL, HFILL }},

        { &hf_wsmp_wsmlength,

          { "WSM Length", "wsmp.wsmlength", FT_UINT16, BASE_DEC, NULL, 0x0,

            NULL, HFILL }},

        { &hf_wsmp_WSMP_S_data,

          { "WAVE Supplement Data", "wsmp.supplement", FT_UINT8, BASE_HEX, NULL, 0x0,

            NULL, HFILL }},

        { &hf_wsmp_subtype,

          { "Subtype", "wsmp.subtype", FT_UINT8, BASE_DEC, VALS(wsmp_subtype_vals), 0xF0,

            NULL, HFILL }},

        { &hf_wsmp_N_header_opt_ind,

          { "WSMP-NHeader Option Indicator(WAVE Information Element Extension)", "wsmp.N_header_opt_ind", FT_BOOLEAN, 8, TFS(&tfs_present_not_present), 0x08,

            NULL, HFILL }},

        { &hf_wsmp_version_v3,

          { "Version", "wsmp.version_v3", FT_UINT8, BASE_DEC, NULL, 0x07,

            NULL, HFILL }},

        { &hf_wsmp_no_elements,

          { "Count", "wsmp.no_elements", FT_UINT16, BASE_DEC, NULL, 0x0,

            NULL, HFILL }},

        { &hf_wsmp_wave_ie,

          { "WAVE IE", "wsmp.wave_ie", FT_UINT8, BASE_DEC, VALS(wsmp_wave_information_elements_vals), 0x0,

            NULL, HFILL }},

        { &hf_wsmp_wave_ie_len,

          { "Length", "wsmp.wave_ie_len", FT_UINT16, BASE_DEC, NULL, 0x0,

            NULL, HFILL }},

        { &hf_wsmp_wave_ie_data,

          { "Data", "wsmp.wave_ie_data", FT_BYTES, BASE_NONE, NULL, 0x0,

            NULL, HFILL }},

        { &hf_wsmp_tpid,

          { "TPID", "wsmp.tpid", FT_UINT8, BASE_DEC, VALS(wsmp_tpid_vals), 0x0,

            NULL, HFILL }},

    };

    /* Setup protocol subtree array */

    static int *ett[] = {

        &ett_wsmp,

        &ett_wsmdata,

        &ett_wsmp_n_hdr,

        &ett_wsmp_t_hdr,

        &ett_wsmp_ie_ext,

        &ett_wsmp_ie,

    };

    static ei_register_info ei[] = {

    { &ei_wsmp_length_field_err, { "wsmp.length_field_err", PI_PROTOCOL, PI_ERROR,

        "Length field wrongly encoded, b6 not 0. The rest of the dissection is suspect", EXPFILL }},

    { &ei_wsmp_psid_invalid, { "wsmp.psid.invalid", PI_PROTOCOL, PI_ERROR, "Invalid PSID", EXPFILL }},

    };

    expert_module_t* expert_wsmp;

    /* Register the protocol name and description */

    proto_wsmp = proto_register_protocol("Wave Short Message Protocol(IEEE P1609.3)",

                                         "WSMP", "wsmp");

    /* Required function calls to register the header fields and subtrees used */

    proto_register_field_array(proto_wsmp, hf, array_length(hf));

    proto_register_subtree_array(ett, array_length(ett));

    expert_wsmp = expert_register_protocol(proto_wsmp);

    expert_register_field_array(expert_wsmp, ei, array_length(ei));

    /* Register the dissector handle */

    wsmp_handle = register_dissector("wsmp", dissect_wsmp, proto_wsmp);

    /* Register IEEE 1609.2 PSIDs dissector table */

    ieee1609dot2_psid_table = register_dissector_table("wsmp.psid",

                                                       "WSMP known PSIDs",

                                                       proto_wsmp,

                                                       FT_UINT32,

                                                       BASE_DEC);

}

void

proto_reg_handoff_wsmp(void)

{

    dissector_add_uint("ethertype", ETHERTYPE_WSMP, wsmp_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:

 */