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/* packet-udt.c
 *
 * Routines for UDT packet dissection
 *
 * Copyright 2013 (c) chas williams <chas@cmf.nrl.navy.mil>
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * Copied from packet-tftp.c
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "config.h"

#include <epan/packet.h>
#include <epan/conversation.h>
#include <epan/expert.h>

/*
 * based on http://tools.ietf.org/html/draft-gg-udt-03
 */

#define UDT_TYPE_DATA                   0
#define UDT_TYPE_CONTROL                1

#define UDT_PACKET_TYPE_HANDSHAKE       0x0000
#define UDT_PACKET_TYPE_KEEPALIVE       0x0001
#define UDT_PACKET_TYPE_ACK             0x0002
#define UDT_PACKET_TYPE_NAK             0x0003
#define UDT_PACKET_TYPE_SHUTDOWN        0x0005
#define UDT_PACKET_TYPE_ACK2            0x0006

#define UDT_HANDSHAKE_TYPE_STREAM       0
#define UDT_HANDSHAKE_TYPE_DGRAM        1

void proto_register_udt(void);
void proto_reg_handoff_udt(void);

static const value_string udt_packet_types[] = {
        {UDT_PACKET_TYPE_HANDSHAKE, "handshake"},
        {UDT_PACKET_TYPE_KEEPALIVE, "keepalive"},
        {UDT_PACKET_TYPE_ACK,       "ack"},
        {UDT_PACKET_TYPE_NAK,       "nak"},
        {UDT_PACKET_TYPE_SHUTDOWN,  "shutdown"},
        {UDT_PACKET_TYPE_ACK2,      "ack2"},
        {0, NULL},
};

static const value_string udt_handshake_types[] = {
        {UDT_HANDSHAKE_TYPE_STREAM, "STREAM"},
        {UDT_HANDSHAKE_TYPE_DGRAM,  "DGRAM"},
        {0, NULL},
};

static const value_string udt_types[] = {
        {UDT_TYPE_DATA,    "DATA"},
        {UDT_TYPE_CONTROL, "CONTROL"},
        {0, NULL},
};

static int proto_udt = -1;
static int hf_udt_iscontrol = -1;
static int hf_udt_type = -1;
static int hf_udt_seqno = -1;
static int hf_udt_ack_seqno = -1;
static int hf_udt_ackno = -1;
static int hf_udt_msgno = -1;
static int hf_udt_msgno_first = -1;
static int hf_udt_msgno_last = -1;
static int hf_udt_msgno_inorder = -1;
static int hf_udt_timestamp = -1;
static int hf_udt_id = -1;
static int hf_udt_addinfo = -1;
static int hf_udt_rtt = -1;
static int hf_udt_rttvar = -1;
static int hf_udt_bufavail = -1;
static int hf_udt_rate = -1;
static int hf_udt_linkcap = -1;
static int hf_udt_handshake_version = -1;
static int hf_udt_handshake_type = -1;
static int hf_udt_handshake_isn = -1;
static int hf_udt_handshake_mtu = -1;
static int hf_udt_handshake_flow_window = -1;
static int hf_udt_handshake_reqtype = -1;
static int hf_udt_handshake_id = -1;
static int hf_udt_handshake_cookie = -1;
static int hf_udt_handshake_peerip = -1;

static gint ett_udt = -1;

static expert_field ei_udt_nak_seqno = EI_INIT;

static dissector_handle_t udt_handle;

static int
dissect_udt(tvbuff_t *tvb, packet_info* pinfo, proto_tree *parent_tree,
            void *data _U_)
{
        proto_tree *tree;
        proto_item *udt_item;
        int         is_control, type;
        guint       i;

        col_set_str(pinfo->cinfo, COL_PROTOCOL, "UDT");
        col_clear(pinfo->cinfo, COL_INFO);

        is_control = tvb_get_ntohl(tvb, 0) & 0x80000000;
        type = (tvb_get_ntohl(tvb, 0) >> 16) & 0x7fff;

        if (is_control)
                col_add_fstr(pinfo->cinfo, COL_INFO, "UDT type: %s  id: %x",
                             val_to_str(type, udt_packet_types,
                                        "Unknown Control Type (%x)"),
                             tvb_get_ntohl(tvb, 12));
        else
                col_add_fstr(pinfo->cinfo, COL_INFO,
                             "UDT type: data  seqno: %u  msgno: %u  id: %x",
                             tvb_get_ntohl(tvb, 0) & 0x7fffffff,
                             tvb_get_ntohl(tvb, 4) & 0x1fffffff,
                             tvb_get_ntohl(tvb, 12));

        udt_item = proto_tree_add_item(parent_tree, proto_udt, tvb,
                                              0, -1, ENC_NA);
        tree = proto_item_add_subtree(udt_item, ett_udt);

        proto_tree_add_item(tree, hf_udt_iscontrol, tvb, 0, 4, ENC_BIG_ENDIAN);
        if (is_control) {
                if (tree) {
                        proto_tree_add_item(tree, hf_udt_type, tvb, 0, 2,
                                            ENC_BIG_ENDIAN);
                        switch (type) {
                        case UDT_PACKET_TYPE_ACK:
                                proto_tree_add_item(tree, hf_udt_ackno, tvb, 4, 4,
                                                    ENC_BIG_ENDIAN);
                                break;
                        case UDT_PACKET_TYPE_ACK2:
                                proto_tree_add_item(tree, hf_udt_ackno, tvb, 4, 4,
                                                    ENC_BIG_ENDIAN);
                                break;
                        default:
                                proto_tree_add_item(tree, hf_udt_addinfo, tvb, 4, 4,
                                                    ENC_BIG_ENDIAN);
                        }
                        proto_tree_add_item(tree, hf_udt_timestamp, tvb, 8, 4,
                                            ENC_BIG_ENDIAN);
                        proto_tree_add_item(tree, hf_udt_id, tvb, 12, 4,
                                            ENC_BIG_ENDIAN);
                }

                switch (type) {
                case UDT_PACKET_TYPE_HANDSHAKE:
                        if (tree) {
                                proto_tree_add_item(tree, hf_udt_handshake_version, tvb,
                                                    16,  4, ENC_BIG_ENDIAN);
                                proto_tree_add_item(tree, hf_udt_handshake_type, tvb,
                                                    20,  4, ENC_BIG_ENDIAN);
                                proto_tree_add_item(tree, hf_udt_handshake_isn, tvb,
                                                    24,  4, ENC_BIG_ENDIAN);
                                proto_tree_add_item(tree, hf_udt_handshake_mtu, tvb,
                                                    28,  4, ENC_BIG_ENDIAN);
                                proto_tree_add_item(tree, hf_udt_handshake_flow_window, tvb,
                                                    32,  4, ENC_BIG_ENDIAN);
                                proto_tree_add_item(tree, hf_udt_handshake_reqtype, tvb,
                                                    36,  4, ENC_BIG_ENDIAN);
                                proto_tree_add_item(tree, hf_udt_handshake_id, tvb,
                                                    40,  4, ENC_BIG_ENDIAN);
                                proto_tree_add_item(tree, hf_udt_handshake_cookie, tvb,
                                                    44,  4, ENC_BIG_ENDIAN);
                                proto_tree_add_item(tree, hf_udt_handshake_peerip, tvb,
                                                    48, 16, ENC_NA);
                                proto_item_set_len(udt_item, 64);
                        }
                        break;
                case UDT_PACKET_TYPE_ACK:
                        if (tree) {
                                proto_tree_add_item(tree, hf_udt_ack_seqno, tvb, 16, 4,
                                                    ENC_BIG_ENDIAN);
                                proto_tree_add_item(tree, hf_udt_rtt,      tvb, 20, 4,
                                                    ENC_BIG_ENDIAN);
                                proto_tree_add_item(tree, hf_udt_rttvar,   tvb, 24, 4,
                                                    ENC_BIG_ENDIAN);
                                proto_tree_add_item(tree, hf_udt_bufavail, tvb, 28, 4,
                                                    ENC_BIG_ENDIAN);
                                /* if not a light ack, decode the rate and link capacity */
                                if (tvb_reported_length(tvb) == 40) {
                                        proto_tree_add_item(tree, hf_udt_rate, tvb,
                                                            32, 4, ENC_BIG_ENDIAN);
                                        proto_tree_add_item(tree, hf_udt_linkcap, tvb,
                                                            36, 4, ENC_BIG_ENDIAN);
                                        proto_item_set_len(udt_item, 40);
                                }
                                else
                                {
                                        proto_item_set_len(udt_item, 32);
                                }
                        }
                        break;
                case UDT_PACKET_TYPE_NAK:
                        for (i = 16; i < tvb_reported_length(tvb); i = i + 4) {
                                guint32 start, finish;
                                int     is_range;

                                is_range = tvb_get_ntohl(tvb, i) & 0x80000000;
                                start = tvb_get_ntohl(tvb, i) & 0x7fffffff;

                                if (is_range) {
                                        finish = tvb_get_ntohl(tvb, i + 4) & 0x7fffffff;

                                        proto_tree_add_expert_format(tree, pinfo, &ei_udt_nak_seqno,
                                                                        tvb, i, 8, "Missing Sequence Number(s): %u-%u",
                                                                    start, finish);
                                        i = i + 4;
                                } else {
                                        proto_tree_add_expert_format(tree, pinfo, &ei_udt_nak_seqno,
                                                                    tvb, i, 4, "Missing Sequence Number: %u",
                                                                    start);
                                }
                        }

                        proto_item_set_len(udt_item, tvb_reported_length(tvb));
                        break;
                }
        } else {
                /* otherwise, a data packet */
                tvbuff_t *next_tvb;

                if (tree) {
                        proto_tree_add_item(tree, hf_udt_seqno,         tvb,  0, 4,
                                            ENC_BIG_ENDIAN);
                        proto_tree_add_item(tree, hf_udt_msgno_first,   tvb,  4, 4,
                                            ENC_BIG_ENDIAN);
                        proto_tree_add_item(tree, hf_udt_msgno_last,    tvb,  4, 4,
                                            ENC_BIG_ENDIAN);
                        proto_tree_add_item(tree, hf_udt_msgno_inorder, tvb,  4, 4,
                                            ENC_BIG_ENDIAN);
                        proto_tree_add_item(tree, hf_udt_msgno,         tvb,  4, 4,
                                            ENC_BIG_ENDIAN);
                        proto_tree_add_item(tree, hf_udt_timestamp,     tvb,  8, 4,
                                            ENC_BIG_ENDIAN);
                        proto_tree_add_item(tree, hf_udt_id,            tvb, 12, 4,
                                            ENC_BIG_ENDIAN);

                }
                next_tvb = tvb_new_subset_remaining(tvb, 16);
                call_data_dissector(next_tvb, pinfo, tree);
        }

        return tvb_reported_length(tvb);
}

static gboolean
dissect_udt_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
{
        conversation_t *conv;

        /* Must have at least 24 captured bytes for heuristic check */
        if (tvb_captured_length(tvb) < 24)
                return FALSE;

        /* detect handshake control packet */
        if (tvb_get_ntohl(tvb, 0) != (0x80000000 | UDT_PACKET_TYPE_HANDSHAKE))
                return FALSE;

        /* must be version 4 */
        if ((tvb_get_ntohl(tvb, 16) != 4))
                return FALSE;

        /* must be datagram or stream */
        if ((tvb_get_ntohl(tvb, 20) != UDT_HANDSHAKE_TYPE_DGRAM)
            && (tvb_get_ntohl(tvb, 20) != UDT_HANDSHAKE_TYPE_STREAM))
                return FALSE;

        conv = find_or_create_conversation(pinfo);
        conversation_set_dissector(conv, udt_handle);
        dissect_udt(tvb, pinfo, tree, data);

        return TRUE;
}

void proto_register_udt(void)
{
        expert_module_t *expert_udt;

        static hf_register_info hf[] = {
                {&hf_udt_iscontrol, {
                                "Type", "udt.iscontrol",
                                 FT_UINT32, BASE_DEC,
                                VALS(udt_types), 0x80000000, NULL, HFILL}},

                {&hf_udt_type, {
                                "Type", "udt.type",
                                FT_UINT16, BASE_HEX,
                                VALS(udt_packet_types), 0x7fff, NULL, HFILL}},

                {&hf_udt_seqno, {
                                "Sequence Number", "udt.seqno",
                                FT_UINT32, BASE_DEC,
                                NULL, 0x7fffffff, NULL, HFILL}},

                {&hf_udt_addinfo, {
                                "Additional Info", "udt.addinfo",
                                FT_UINT32, BASE_DEC,
                                NULL, 0, NULL, HFILL}},

                {&hf_udt_msgno, {
                                "Message Number", "udt.msgno",
                                FT_UINT32, BASE_DEC,
                                NULL, 0x1fffffff, NULL, HFILL}},

                {&hf_udt_msgno_first, {
                                "First Indicator", "udt.msg.first",
                                FT_UINT32, BASE_DEC,
                                NULL, 0x80000000, NULL, HFILL}},

                {&hf_udt_msgno_last, {
                                "Last Indicator", "udt.msg.last",
                                FT_UINT32, BASE_DEC,
                                NULL, 0x40000000, NULL, HFILL}},

                {&hf_udt_msgno_inorder, {
                                "In-Order Indicator", "udt.msg.order",
                                FT_UINT32, BASE_DEC,
                                NULL, 0x20000000, NULL, HFILL}},

                {&hf_udt_timestamp, {
                                "Timestamp", "udt.timestamp",
                                FT_UINT32, BASE_DEC,
                                NULL, 0, NULL, HFILL}},

                {&hf_udt_id, {
                                "ID", "udt.id",
                                FT_UINT32, BASE_HEX,
                                NULL, 0, NULL, HFILL}},

                {&hf_udt_ack_seqno, {
                                "Ack Sequence Number", "udt.ack_seqno",
                                FT_UINT32, BASE_DEC,
                                NULL, 0, NULL, HFILL}},

                {&hf_udt_ackno, {
                                "Ack Number", "udt.ackno",
                                FT_UINT32, BASE_DEC,
                                NULL, 0, NULL, HFILL}},

                {&hf_udt_rtt, {
                                "RTT (microseconds)", "udt.rtt",
                                FT_UINT32, BASE_DEC,
                                NULL, 0, NULL, HFILL}},

                {&hf_udt_rttvar, {
                                "RTT Variance (microseconds)", "udt.rttvar",
                                FT_UINT32, BASE_DEC,
                                NULL, 0, NULL, HFILL}},

                {&hf_udt_bufavail, {
                                "Buffer Available (packets)", "udt.rttvar",
                                FT_UINT32, BASE_DEC,
                                NULL, 0, NULL, HFILL}},

                {&hf_udt_rate, {
                                "Rate (packets/second)", "udt.rate",
                                FT_UINT32, BASE_DEC,
                                NULL, 0, NULL, HFILL}},

                {&hf_udt_linkcap, {
                                "Link Capacity (packets/second)", "udt.linkcap",
                                FT_UINT32, BASE_DEC,
                                NULL, 0, NULL, HFILL}},

                {&hf_udt_handshake_version, {
                                "Version", "udt.hs.version",
                                FT_UINT32, BASE_DEC,
                                NULL, 0, NULL, HFILL}},

                {&hf_udt_handshake_type, {
                                "Type", "udt.hs.type",
                                FT_UINT32, BASE_DEC,
                                VALS(udt_handshake_types), 0, NULL,
                                HFILL}},

                {&hf_udt_handshake_isn, {
                                "Initial Sequence Number", "udt.hs.isn",
                                FT_UINT32, BASE_DEC,
                                NULL, 0, NULL, HFILL}},

                {&hf_udt_handshake_mtu, {
                                "MTU", "udt.hs.mtu",
                                FT_UINT32, BASE_DEC,
                                NULL, 0, NULL, HFILL}},

                {&hf_udt_handshake_flow_window, {
                                "Flow Window", "udt.hs.flow_window",
                                FT_UINT32, BASE_DEC,
                                NULL, 0, NULL, HFILL}},

                {&hf_udt_handshake_reqtype, {
                                "Requested Type", "udt.hs.reqtype",
                                FT_INT32, BASE_DEC,
                                NULL, 0, NULL, HFILL}},

                {&hf_udt_handshake_id, {
                                "ID", "udt.hs.id",
                                FT_UINT32, BASE_DEC,
                                NULL, 0, NULL, HFILL}},

                {&hf_udt_handshake_cookie, {
                                "SYN Cookie", "udt.hs.cookie",
                                FT_UINT32, BASE_HEX,
                                NULL, 0, NULL, HFILL}},

                {&hf_udt_handshake_peerip, {
                                "Peer IP Address", "udt.hs.peerip",
                                FT_BYTES, BASE_NONE,
                                NULL, 0, NULL, HFILL}},
        };

        static gint *ett[] = {
                &ett_udt,
        };

        static ei_register_info ei[] = {
                { &ei_udt_nak_seqno,
                  { "udt.nak_seqno", PI_SEQUENCE, PI_NOTE,
                    "Missing Sequence Number(s)", EXPFILL }},
        };

        proto_udt = proto_register_protocol("UDT Protocol", "UDT", "udt");
        proto_register_field_array(proto_udt, hf, array_length(hf));
        proto_register_subtree_array(ett, array_length(ett));

        expert_udt = expert_register_protocol(proto_udt);
        expert_register_field_array(expert_udt, ei, array_length(ei));
}

void proto_reg_handoff_udt(void)
{
        udt_handle  = create_dissector_handle(dissect_udt, proto_udt);

        heur_dissector_add("udp", dissect_udt_heur, "UDT over UDP", "udt_udp", proto_udt, HEURISTIC_ENABLE);
        dissector_add_for_decode_as("udp.port", udt_handle);
}


/*
 * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
 *
 * Local variables:
 * c-basic-offset: 8
 * tab-width: 8
 * indent-tabs-mode: t
 * End:
 *
 * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 * :indentSize=8:tabSize=8:noTabs=false:
 */