/* packet-brdwlk.c

 * Routines for decoding MDS Port Analyzer Adapter (FC in Eth) Header

 * Copyright 2001, Dinesh G Dutt <ddutt@andiamo.com>

 *

 * Wireshark - Network traffic analyzer

 * By Gerald Combs <gerald@wireshark.org>

 * Copyright 1998 Gerald Combs

 *

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

 */

/*

 * https://www.cisco.com/en/US/docs/storage/san_switches/mds9000/hw/paa/installation/note/FPAA2.pdf

 * https://www.cisco.com/en/US/docs/storage/san_switches/mds9000/hw/paa/installation/note/FPAA2.html

 */

#include "config.h"

#include <epan/packet.h>

#include <epan/proto_data.h>

#include <epan/tfs.h>

#include "packet-fc.h"

#define BRDWLK_MAX_PACKET_CNT  0xFFFF

#define BRDWLK_TRUNCATED_BIT   0x8

#define BRDWLK_HAS_PLEN        0x1

#define FCM_DELIM_SOFC1         0x01

#define FCM_DELIM_SOFI1         0x02

#define FCM_DELIM_SOFI2         0x04

#define FCM_DELIM_SOFI3         0x06

#define FCM_DELIM_SOFN1         0x03

#define FCM_DELIM_SOFN2         0x05

#define FCM_DELIM_SOFN3         0x07

#define FCM_DELIM_SOFF          0x08

#define FCM_DELIM_SOFC4         0x09

#define FCM_DELIM_SOFI4         0x0A

#define FCM_DELIM_SOFN4         0x0B

#define FCM_DELIM_EOFT          0x01

#define FCM_DELIM_EOFDT         0x02

#define FCM_DELIM_EOFN          0x03

#define FCM_DELIM_EOFA          0x04

#define FCM_DELIM_EOFNI         0x07

#define FCM_DELIM_EOFDTI        0x06

#define FCM_DELIM_EOFRT         0x0A

#define FCM_DELIM_EOFRTI        0x0E

#define FCM_DELIM_NOEOF         0xF0

#define FCM_DELIM_EOFJUMBO      0xF1

void proto_register_brdwlk(void);

void proto_reg_handoff_brdwlk(void);

static const value_string brdwlk_sof_vals[] = {

    {FCM_DELIM_SOFI1, "SOFi1"},

    {FCM_DELIM_SOFI2, "SOFi2"},

    {FCM_DELIM_SOFI3, "SOFi3"},

    {FCM_DELIM_SOFN1, "SOFn1"},

    {FCM_DELIM_SOFN2, "SOFn2"},

    {FCM_DELIM_SOFN3, "SOFn3"},

    {FCM_DELIM_SOFF,  "SOFf"},

    {0, NULL},

};

static const value_string brdwlk_eof_vals[] = {

    {FCM_DELIM_EOFDT, "EOFdt"},

    {FCM_DELIM_EOFA,  "EOFa"},

    {FCM_DELIM_EOFN,  "EOFn"},

    {FCM_DELIM_EOFT,  "EOFt"},

    {0, NULL},

};

static int hf_brdwlk_sof;

static int hf_brdwlk_eof;

static int hf_brdwlk_error;

static int hf_brdwlk_vsan;

static int hf_brdwlk_pktcnt;

static int hf_brdwlk_drop;

static int hf_brdwlk_plen;

static int hf_brdwlk_error_plp;

static int hf_brdwlk_error_ef;

static int hf_brdwlk_error_nd;

static int hf_brdwlk_error_tr;

static int hf_brdwlk_error_badcrc;

static int hf_brdwlk_error_ff;

static int hf_brdwlk_error_jumbo;

static int hf_brdwlk_error_ctrl;

/* Initialize the subtree pointers */

static int ett_brdwlk;

static int ett_brdwlk_error;

static int proto_brdwlk;

static uint16_t packet_count;

static bool first_pkt = true;                /* start of capture */

static dissector_handle_t fc_dissector_handle;

static dissector_handle_t brdwlk_handle;

static const true_false_string tfs_error_plp = {

    "Packet Length is PRESENT",

    "Packet length is NOT present"

};

static const true_false_string tfs_error_ef = {

    "This is an Empty Frame",

    "Frame is NOT empty"

};

static const true_false_string tfs_error_nd = {

    "This Frame has NO Data",

    "This frame carries data"

};

static const true_false_string tfs_error_tr = {

    "This frame is TRUNCATED",

    "This frame is NOT truncated"

};

static const true_false_string tfs_error_crc = {

    "This Frame has a BAD FC CRC",

    "This frame has a valid crc"

};

static const true_false_string tfs_error_ff = {

    "Fifo is Full",

    "Fifo is NOT full"

};

static const true_false_string tfs_error_jumbo = {

    "This is a JUMBO FC Frame",

    "This is a NORMAL FC Frame"

};

static const true_false_string tfs_error_ctrl = {

    "Ctrl Characters inside the frame",

    "No ctrl chars inside the frame"

};

static void

dissect_brdwlk_err(proto_tree *parent_tree, tvbuff_t *tvb, int offset)

{

    static int * const flags[] = {

        &hf_brdwlk_error_plp,

        &hf_brdwlk_error_ef,

        &hf_brdwlk_error_nd,

        &hf_brdwlk_error_tr,

        &hf_brdwlk_error_badcrc,

        &hf_brdwlk_error_ff,

        &hf_brdwlk_error_jumbo,

        &hf_brdwlk_error_ctrl,

        NULL

    };

    proto_tree_add_bitmask_with_flags(parent_tree, tvb, offset, hf_brdwlk_error, ett_brdwlk_error, flags, ENC_NA, BMT_NO_FALSE|BMT_NO_TFS);

}

/* Code to actually dissect the packets */

static int

dissect_brdwlk(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, *hidden_item;

    proto_tree *brdwlk_tree;

    tvbuff_t *next_tvb;

    uint8_t error, eof, sof;

    int hdrlen = 2,

        offset = 0;

    int len, reported_len, plen;

    uint16_t pkt_cnt;

    bool dropped_packets;

    fc_data_t fc_data;

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

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

    col_clear(pinfo->cinfo, COL_INFO);

    sof = (tvb_get_uint8(tvb, offset) & 0xF0) >> 4;

    fc_data.sof_eof = 0;

    if ((sof == FCM_DELIM_SOFI3) || (sof == FCM_DELIM_SOFI2) || (sof == FCM_DELIM_SOFI1)

        || (sof == FCM_DELIM_SOFI4)) {

        fc_data.sof_eof = FC_DATA_SOF_FIRST_FRAME;

    }

    else if (sof == FCM_DELIM_SOFF) {

        fc_data.sof_eof = FC_DATA_SOF_SOFF;

    }

    ti = proto_tree_add_protocol_format(tree, proto_brdwlk, tvb, 0,

            hdrlen, "Boardwalk");

    brdwlk_tree = proto_item_add_subtree(ti, ett_brdwlk);

    proto_tree_add_item(brdwlk_tree, hf_brdwlk_sof, tvb, offset, 1, ENC_BIG_ENDIAN);

    proto_tree_add_item(brdwlk_tree, hf_brdwlk_vsan, tvb, offset, 2, ENC_BIG_ENDIAN);

    /* Locate EOF which is the last 4 bytes of the frame */

    len = tvb_captured_length_remaining(tvb, hdrlen);

    reported_len = tvb_reported_length_remaining(tvb, hdrlen);

    if (reported_len < 4) {

        /*

         * This packet is claimed not to even have enough data for

         * a 4-byte EOF.

         * Don't try to process the EOF.

         */

        ;

    }

    else if (len < reported_len) {

        /*

         * This packet is claimed to have enough data for a 4-byte EOF,

         * but we didn't capture all of the packet.

         * Slice off the 4-byte EOF from the reported length, and trim

         * the captured length so it's no more than the reported length;

         * that will slice off what of the EOF, if any, is in the

         * captured length.

         */

        reported_len -= 4;

        if (len > reported_len)

            len = reported_len;

    }

    else {

        /*

         * We have the entire packet, and it includes a 4-byte EOF.

         * Slice it off, and put it into the tree if we're building

         * a tree.

         */

        len -= 4;

        reported_len -= 4;

        offset = tvb_reported_length(tvb) - 4;

        pkt_cnt = tvb_get_ntohs(tvb, offset);

        if (tree) {

            proto_tree_add_uint(brdwlk_tree, hf_brdwlk_pktcnt, tvb, offset,

                                2, pkt_cnt);

        }

        dropped_packets = false;

        if (pinfo->fd->visited) {

            /*

             * This isn't the first pass, so we can't use the global

             * "packet_count" variable to determine whether there were

             * any dropped frames or not.

             * We therefore attach a non-null pointer as frame data to

             * any frame preceded by dropped packets.

             */

            if (p_get_proto_data(wmem_file_scope(), pinfo, proto_brdwlk, 0) != NULL)

                dropped_packets = true;

        } else {

            /*

             * This is the first pass, so we have to use the global

             * "packet_count" variable to determine whether there were

             * any dropped frames or not.

             *

             * XXX - can there be more than one stream of packets, so that

             * we can't just use a global variable?

             */

            if (pkt_cnt != packet_count + 1) {

                if (!first_pkt &&

                    (pkt_cnt != 0 || (packet_count != BRDWLK_MAX_PACKET_CNT))) {

                    dropped_packets = true;

                    /*

                     * Mark this frame as having been preceded by dropped

                     * packets.  (The data we use as the frame data doesn't

                     * matter - it just matters that it's non-null.)

                     */

                    p_add_proto_data(wmem_file_scope(), pinfo, proto_brdwlk, 0, &packet_count);

                }

            }

        }

        hidden_item = proto_tree_add_boolean(brdwlk_tree, hf_brdwlk_drop,

                tvb, offset, 0, dropped_packets);

        proto_item_set_hidden(hidden_item);

        packet_count = pkt_cnt;

        error=tvb_get_uint8(tvb, offset+2);

        dissect_brdwlk_err(brdwlk_tree, tvb, offset+2);

        eof = tvb_get_uint8(tvb, offset+3);

        if (eof != FCM_DELIM_EOFN) {

            fc_data.sof_eof |= FC_DATA_EOF_LAST_FRAME;

        }

        else if (eof != FCM_DELIM_EOFT) {

            fc_data.sof_eof |= FC_DATA_EOF_INVALID;

        }

        proto_tree_add_item(brdwlk_tree, hf_brdwlk_eof, tvb, offset+3,

                1, ENC_BIG_ENDIAN);

        if ((error & BRDWLK_HAS_PLEN) && tree) {

            /* In newer Boardwalks, if this bit is set, the actual frame length

             * is also provided. This length is the size between SOF & EOF

             * including FC CRC, measured in words.

             *

             * XXX - It should be between 12 (36 bytes) and 528 (2112 bytes).

             */

            plen = tvb_get_ntohs(tvb, offset-4);

            plen *= 4;

            proto_tree_add_uint(brdwlk_tree, hf_brdwlk_plen, tvb, offset-4,

                                2, plen);

            if (error & BRDWLK_TRUNCATED_BIT) {

#if 0

                /* XXX - this would throw an exception if it would increase

                 * the reported length. If it would decrease the reported

                 * length, tvb_set_reported_length is used to help the Ethernet

                 * dissector find a trailer - except that wouldn't work because

                 * the EOF is located from the end of the frame, i.e. trailer

                 * heuristics never work with this dissector.

                 */

                tvb_set_reported_length(tvb, plen);

#endif

                /* Set the reported length for the FC subset tvb. */

                reported_len = plen;

            }

        }

    }

    fc_data.ethertype = ETHERTYPE_BRDWALK;

    next_tvb = tvb_new_subset_length_caplen(tvb, 2, len, reported_len);

    call_dissector_with_data(fc_dissector_handle, next_tvb, pinfo, tree, &fc_data);

    return tvb_captured_length(tvb);

}

static void

brdwlk_init(void)

{

    packet_count = 0;

    first_pkt = true;

}

/* Register the protocol with Wireshark */

/* this format is require because a script is used to build the C function

   that calls all the protocol registration.

*/

void

proto_register_brdwlk(void)

{

/* Setup list of header fields  See Section 1.6.1 for details*/

    static hf_register_info hf[] = {

        { &hf_brdwlk_sof,

          {"SOF", "brdwlk.sof", FT_UINT8, BASE_HEX, VALS(brdwlk_sof_vals),

           0xF0, NULL, HFILL}},

        { &hf_brdwlk_eof,

          {"EOF", "brdwlk.eof", FT_UINT8, BASE_HEX, VALS(brdwlk_eof_vals),

           0x0F, NULL, HFILL}},

        { &hf_brdwlk_error,

          {"Error", "brdwlk.error", FT_UINT8, BASE_HEX, NULL, 0x0, NULL,

           HFILL}},

        { &hf_brdwlk_pktcnt,

          {"Packet Count", "brdwlk.pktcnt", FT_UINT16, BASE_DEC, NULL, 0x0,

           NULL, HFILL}},

        { &hf_brdwlk_drop,

          {"Packet Dropped", "brdwlk.drop", FT_BOOLEAN, BASE_NONE, NULL, 0x0,

           NULL, HFILL}},

        { &hf_brdwlk_vsan,

          {"VSAN", "brdwlk.vsan", FT_UINT16, BASE_DEC, NULL, 0x0FFF, NULL,

           HFILL}},

        { &hf_brdwlk_plen,

          {"Original Packet Length", "brdwlk.plen", FT_UINT32, BASE_DEC, NULL, 0x0, NULL,

           HFILL}},

        { &hf_brdwlk_error_plp,

          {"Packet Length Present", "brdwlk.error.plp", FT_BOOLEAN, 8, TFS(&tfs_error_plp), 0x01, NULL,

           HFILL}},

        { &hf_brdwlk_error_ef,

          {"Empty Frame", "brdwlk.error.ef", FT_BOOLEAN, 8, TFS(&tfs_error_ef), 0x02, NULL,

           HFILL}},

        { &hf_brdwlk_error_nd,

          {"No Data", "brdwlk.error.nd", FT_BOOLEAN, 8, TFS(&tfs_error_nd), 0x04, NULL,

           HFILL}},

        { &hf_brdwlk_error_tr,

          {"Truncated", "brdwlk.error.tr", FT_BOOLEAN, 8, TFS(&tfs_error_tr), 0x08, NULL,

           HFILL}},

        { &hf_brdwlk_error_badcrc,

          {"CRC", "brdwlk.error.crc", FT_BOOLEAN, 8, TFS(&tfs_error_crc), 0x10, NULL,

           HFILL}},

        { &hf_brdwlk_error_ff,

          {"Fifo Full", "brdwlk.error.ff", FT_BOOLEAN, 8, TFS(&tfs_error_ff), 0x20, NULL,

           HFILL}},

        { &hf_brdwlk_error_jumbo,

          {"Jumbo FC Frame", "brdwlk.error.jumbo", FT_BOOLEAN, 8, TFS(&tfs_error_jumbo), 0x40, NULL,

           HFILL}},

        { &hf_brdwlk_error_ctrl,

          {"Ctrl Char Inside Frame", "brdwlk.error.ctrl", FT_BOOLEAN, 8, TFS(&tfs_error_ctrl), 0x80, NULL,

           HFILL}},

    };

/* Setup protocol subtree array */

    static int *ett[] = {

        &ett_brdwlk,

        &ett_brdwlk_error,

    };

/* Register the protocol name and description */

    proto_brdwlk = proto_register_protocol("Boardwalk", "Boardwalk", "brdwlk");

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

    proto_register_field_array(proto_brdwlk, hf, array_length(hf));

    proto_register_subtree_array(ett, array_length(ett));

    register_init_routine(&brdwlk_init);

/* Register the dissector */

    brdwlk_handle = register_dissector("brdwlk", dissect_brdwlk, proto_brdwlk);

}

void

proto_reg_handoff_brdwlk(void)

{

    dissector_add_uint("ethertype", ETHERTYPE_BRDWALK, brdwlk_handle);

    dissector_add_uint("ethertype", 0xABCD, brdwlk_handle);

    fc_dissector_handle = find_dissector_add_dependency("fc", proto_brdwlk);

}

/*

 * 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:

 */