/* packet-idmp.c
 * Routines for X.519 Internet Directly Mapped Procotol (IDMP) packet dissection
 * Graeme Lunt 2010
 *
 * $Id$
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * 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 <glib.h>
#include <epan/packet.h>
#include <epan/prefs.h>
#include <epan/wmem/wmem.h>
#include <epan/reassemble.h>
#include <epan/conversation.h>
#include <epan/oids.h>
#include <epan/asn1.h>
#include <epan/ipproto.h>

#include <epan/dissectors/packet-tcp.h>

#include "packet-ber.h"
#include "packet-ros.h"
#include "packet-x509ce.h"

#include <epan/strutil.h>

#define PNAME  "X.519 Internet Directly Mapped Protocol"
#define PSNAME "IDMP"
#define PFNAME "idmp"

static gboolean           idmp_desegment       = TRUE;
static guint              global_idmp_tcp_port = 1102; /* made up for now */
static gboolean           idmp_reassemble      = TRUE;
static guint              tcp_port             = 0;
static dissector_handle_t idmp_handle          = NULL;

static proto_tree *top_tree         = NULL;
static const char *protocolID       = NULL;
static const char *saved_protocolID = NULL;
static guint32     opcode           = -1;

static void prefs_register_idmp(void); /* forward declaration for use in preferences registration */

/* Initialize the protocol and registered fields */
int proto_idmp = -1;

static int hf_idmp_version = -1;
static int hf_idmp_final = -1;
static int hf_idmp_length = -1;
static int hf_idmp_PDU = -1;

static reassembly_table idmp_reassembly_table;

static int hf_idmp_fragments = -1;
static int hf_idmp_fragment = -1;
static int hf_idmp_fragment_overlap = -1;
static int hf_idmp_fragment_overlap_conflicts = -1;
static int hf_idmp_fragment_multiple_tails = -1;
static int hf_idmp_fragment_too_long_fragment = -1;
static int hf_idmp_fragment_error = -1;
static int hf_idmp_fragment_count = -1;
static int hf_idmp_reassembled_in = -1;
static int hf_idmp_reassembled_length = -1;

static gint ett_idmp_fragment = -1;
static gint ett_idmp_fragments = -1;

static const fragment_items idmp_frag_items = {
    /* Fragment subtrees */
    &ett_idmp_fragment,
    &ett_idmp_fragments,
    /* Fragment fields */
    &hf_idmp_fragments,
    &hf_idmp_fragment,
    &hf_idmp_fragment_overlap,
    &hf_idmp_fragment_overlap_conflicts,
    &hf_idmp_fragment_multiple_tails,
    &hf_idmp_fragment_too_long_fragment,
    &hf_idmp_fragment_error,
    &hf_idmp_fragment_count,
    /* Reassembled in field */
    &hf_idmp_reassembled_in,
    /* Reassembled length field */
    &hf_idmp_reassembled_length,
    /* Reassembled data field */
    NULL,
    /* Tag */
    "IDMP fragments"
};


static int call_idmp_oid_callback(tvbuff_t *tvb, int offset, packet_info *pinfo, int op, proto_tree *tree, struct SESSION_DATA_STRUCTURE *session)
{
    if(session != NULL) {

        if((!saved_protocolID) && (op == (ROS_OP_BIND | ROS_OP_RESULT))) {
            /* save for subsequent operations - should be into session data */
            saved_protocolID = wmem_strdup(wmem_file_scope(), protocolID);
        }

        /* mimic ROS! */
        session->ros_op = op;
        offset = call_ros_oid_callback(saved_protocolID ? saved_protocolID : protocolID, tvb, offset, pinfo, tree, session);
    }

    return offset;

}

#include "packet-idmp-hf.c"

/* Initialize the subtree pointers */
static gint ett_idmp = -1;
#include "packet-idmp-ett.c"

#include "packet-idmp-fn.c"

void
register_idmp_protocol_info(const char *oid, const ros_info_t *rinfo, int proto _U_, const char *name)
{
    /* just register with ROS for now */
    register_ros_protocol_info(oid, rinfo, proto, name, FALSE);
}


static int dissect_idmp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, void* data _U_)
{
    int offset = 0;

    proto_item                    *item;
    proto_tree                    *tree;
    asn1_ctx_t                     asn1_ctx;
    struct SESSION_DATA_STRUCTURE  session;
    gboolean                       idmp_final;
    guint32                        idmp_length;
    fragment_head                 *fd_head;
    conversation_t                *conv;
    guint32                        dst_ref = 0;

    asn1_ctx_init(&asn1_ctx, ASN1_ENC_BER, TRUE, pinfo);

    conv = find_conversation (pinfo->fd->num, &pinfo->src, &pinfo->dst,
                              pinfo->ptype, pinfo->srcport, pinfo->destport, 0);
    if (conv) {
        /* Found a conversation, also use index for the generated dst_ref */
        dst_ref = conv->index;
    }

    /* save parent_tree so subdissectors can create new top nodes */
    top_tree=parent_tree;

    item = proto_tree_add_item(parent_tree, proto_idmp, tvb, 0, -1, ENC_NA);
    tree = proto_item_add_subtree(item, ett_idmp);

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

    /* now check the segment fields */

    proto_tree_add_item(tree, hf_idmp_version, tvb, offset, 1, ENC_BIG_ENDIAN); offset++;
    proto_tree_add_item(tree, hf_idmp_final, tvb, offset, 1, ENC_BIG_ENDIAN);
    idmp_final = tvb_get_guint8(tvb, offset); offset++;
    proto_tree_add_item(tree, hf_idmp_length, tvb, offset, 4, ENC_BIG_ENDIAN);
    idmp_length = tvb_get_ntohl(tvb, offset); offset += 4;

    asn1_ctx.private_data = &session;

    if(idmp_reassemble) {

        pinfo->fragmented = !idmp_final;

        col_append_fstr(pinfo->cinfo, COL_INFO, " [%sIDMP fragment, %u byte%s]",
                            idmp_final ? "Final " : "" ,
                            idmp_length, plurality(idmp_length, "", "s"));

        fd_head = fragment_add_seq_next(&idmp_reassembly_table, tvb, offset,
                                        pinfo, dst_ref, NULL,
                                        idmp_length, !idmp_final);

        if(fd_head && fd_head->next) {
            proto_tree_add_text(tree, tvb, offset, (idmp_length) ? -1 : 0,
                                "IDMP segment data (%u byte%s)", idmp_length,
                                plurality(idmp_length, "", "s"));

            if (idmp_final) {
                /* This is the last segment */
                tvb = process_reassembled_data (tvb, offset, pinfo,
                                                "Reassembled IDMP", fd_head, &idmp_frag_items, NULL, tree);
                offset = 0;
            } else if (pinfo->fd->num != fd_head->reassembled_in) {
                /* Add a "Reassembled in" link if not reassembled in this frame */
                proto_tree_add_uint (tree, hf_idmp_reassembled_in,
                                     tvb, 0, 0, fd_head->reassembled_in);
            }
        }

    } else {
        if(!idmp_final) {

            col_append_fstr(pinfo->cinfo, COL_INFO, " [IDMP fragment, %u byte%s, IDMP reassembly not enabled]",
                                idmp_length, plurality(idmp_length, "", "s"));

            proto_tree_add_text(tree, tvb, offset, (idmp_length) ? -1 : 0,
                                "IDMP segment data (%u byte%s) (IDMP reassembly not enabled)", idmp_length,
                                plurality(idmp_length, "", "s"));
        }
    }
    /* not reassembling - just dissect */
    if(idmp_final) {
        asn1_ctx.private_data = &session;
        dissect_idmp_IDM_PDU(FALSE, tvb, offset, &asn1_ctx, tree, hf_idmp_PDU);
    }

    return tvb_length(tvb);
}

static guint get_idmp_pdu_len(packet_info *pinfo _U_, tvbuff_t *tvb, int offset)
{
    guint32 len;

    len = tvb_get_ntohl(tvb, offset + 2);

    return len + 6;
}

static int dissect_idmp_tcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, void* data)
{
    tcp_dissect_pdus(tvb, pinfo, parent_tree, idmp_desegment, 0, get_idmp_pdu_len, dissect_idmp, data);
	return tvb_length(tvb);
}

static void idmp_reassemble_init (void)
{
    reassembly_table_init (&idmp_reassembly_table,
                           &addresses_reassembly_table_functions);

    saved_protocolID = NULL;
}

/*--- proto_register_idmp -------------------------------------------*/
void proto_register_idmp(void)
{
    /* List of fields */
    static hf_register_info hf[] = {
        { &hf_idmp_version,
          { "version", "idmp.version",
            FT_INT8, BASE_DEC, NULL, 0,
            "idmp.INTEGER", HFILL }},
        { &hf_idmp_final,
          { "final", "idmp.final",
            FT_BOOLEAN, BASE_NONE, NULL, 0,
            "idmp.BOOLEAN", HFILL }},
        { &hf_idmp_length,
          { "length", "idmp.length",
            FT_INT32, BASE_DEC, NULL, 0,
            "idmp.INTEGER", HFILL }},
        { &hf_idmp_PDU,
          { "IDM-PDU", "idmp.pdu",
            FT_UINT32, BASE_DEC, VALS(idmp_IDM_PDU_vals), 0,
            "idmp.PDU", HFILL }},
        /* Fragment entries */
        { &hf_idmp_fragments,
          { "IDMP fragments", "idmp.fragments", FT_NONE, BASE_NONE,
            NULL, 0x00, NULL, HFILL } },
        { &hf_idmp_fragment,
          { "IDMP fragment", "idmp.fragment", FT_FRAMENUM, BASE_NONE,
            NULL, 0x00, NULL, HFILL } },
        { &hf_idmp_fragment_overlap,
          { "IDMP fragment overlap", "idmp.fragment.overlap", FT_BOOLEAN,
            BASE_NONE, NULL, 0x00, NULL, HFILL } },
        { &hf_idmp_fragment_overlap_conflicts,
          { "IDMP fragment overlapping with conflicting data",
            "idmp.fragment.overlap.conflicts", FT_BOOLEAN, BASE_NONE,
            NULL, 0x00, NULL, HFILL } },
        { &hf_idmp_fragment_multiple_tails,
          { "IDMP has multiple tail fragments",
            "idmp.fragment.multiple_tails", FT_BOOLEAN, BASE_NONE,
            NULL, 0x00, NULL, HFILL } },
        { &hf_idmp_fragment_too_long_fragment,
          { "IDMP fragment too long", "idmp.fragment.too_long_fragment",
            FT_BOOLEAN, BASE_NONE, NULL, 0x00, NULL, HFILL } },
        { &hf_idmp_fragment_error,
          { "IDMP defragmentation error", "idmp.fragment.error", FT_FRAMENUM,
            BASE_NONE, NULL, 0x00, NULL, HFILL } },
        { &hf_idmp_fragment_count,
          { "IDMP fragment count", "idmp.fragment.count", FT_UINT32, BASE_DEC,
            NULL, 0x00, NULL, HFILL } },
        { &hf_idmp_reassembled_in,
          { "Reassembled IDMP in frame", "idmp.reassembled.in", FT_FRAMENUM, BASE_NONE,
            NULL, 0x00, "This IDMP packet is reassembled in this frame", HFILL } },
        { &hf_idmp_reassembled_length,
          { "Reassembled IDMP length", "idmp.reassembled.length", FT_UINT32, BASE_DEC,
            NULL, 0x00, "The total length of the reassembled payload", HFILL } },

#include "packet-idmp-hfarr.c"
    };

    /* List of subtrees */
    static gint *ett[] = {
        &ett_idmp,
        &ett_idmp_fragment,
        &ett_idmp_fragments,
#include "packet-idmp-ettarr.c"
    };
    module_t *idmp_module;

    /* Register protocol */
    proto_idmp = proto_register_protocol(PNAME, PSNAME, PFNAME);

    /* Register fields and subtrees */
    proto_register_field_array(proto_idmp, hf, array_length(hf));
    proto_register_subtree_array(ett, array_length(ett));

    new_register_dissector("idmp", dissect_idmp_tcp, proto_idmp);

    register_init_routine (&idmp_reassemble_init);

    /* Register our configuration options for IDMP, particularly our port */

    idmp_module = prefs_register_protocol_subtree("OSI/X.500", proto_idmp, prefs_register_idmp);

    prefs_register_bool_preference(idmp_module, "desegment_idmp_messages",
                                   "Reassemble IDMP messages spanning multiple TCP segments",
                                   "Whether the IDMP dissector should reassemble messages spanning multiple TCP segments."
                                   " To use this option, you must also enable \"Allow subdissectors to reassemble TCP streams\" in the TCP protocol settings.",
                                   &idmp_desegment);

    prefs_register_bool_preference(idmp_module, "reassemble",
                                   "Reassemble segmented IDMP datagrams",
                                   "Whether segmented IDMP datagrams should be reassembled."
                                   " To use this option, you must also enable"
                                   " \"Allow subdissectors to reassemble TCP streams\""
                                   " in the TCP protocol settings.", &idmp_reassemble);

    prefs_register_uint_preference(idmp_module, "tcp.port", "IDMP TCP Port",
                                   "Set the port for Internet Directly Mapped Protocol requests/responses",
                                   10, &global_idmp_tcp_port);

}


/*--- proto_reg_handoff_idm --- */
void proto_reg_handoff_idm(void) {

    /* remember the idm handler for change in preferences */
    idmp_handle = find_dissector(PFNAME);

}


static void
prefs_register_idmp(void)
{

    /* de-register the old port */
    /* port 102 is registered by TPKT - don't undo this! */
    if(idmp_handle)
        dissector_delete_uint("tcp.port", tcp_port, idmp_handle);

    /* Set our port number for future use */
    tcp_port = global_idmp_tcp_port;

    if((tcp_port > 0) && idmp_handle)
        dissector_add_uint("tcp.port", global_idmp_tcp_port, idmp_handle);

}
