path: root/epan/dissectors/packet-fw1.c

/* packet-fw1.c
 * Routines for Ethernet header disassembly of FW1 "monitor" files
 * Copyright 2002,2003, Alfred Koebler <ako@icon.de>
 * Copyright 2018, Alfred Koebler <Alfred.Koebler2002ATgmx.de>
 *
 * Wireshark - Network traffic analyzer
 * By Alfred Koebler <ako@icon.de>
 * By Alfred Koebler <Alfred.Koebler2002ATgmx.de>
 * Copyright 2002,2003,2018 Alfred Koebler
 *
 * To use this dissector use the command line option
 * -o eth.interpret_as_fw1_monitor:true
 *
 * At the moment the way with the option is the best one.
 * A automatic way is not possible, because the file format isn't different
 * to the snoop file.
 *
 * With "fw monitor" it is possible to collect packets on several places.
 * The additional information:
 * - is it a incoming or outgoing packet
 * - is it before or after the firewall
 *   i  incoming before the firewall
 *   I  incoming after the firewall
 *   o  outcoming before the firewall
 *   O  outcoming after the firewall
 *   e  before VPN encryption
 *   E  after VPN encryption
 * - the name of the interface
 *
 * What's the problem ?
 * Think about one packet traveling across the firewall.
 * With wireshark you will see 4 lines in the Top Pane.
 * To analyze a problem it is helpful to see the additional information
 * in the protocol tree of the Middle Pane.
 *
 * The presentation of the summary line is designed in the following way:
 * Every time the next selected packet in the Top Pane includes a
 * "new" interface name the name is added to the list in the summary line.
 * The interface names are listed one after the other.
 * The position of the interface names didn't change.
 *
 * And who are the 4 places represented ?
 * The interface name represents the firewall module of the interface.
 * On the left side of the interface name is the interface module.
 * On the right side of the interface name is the "IP" module.
 *
 * Example for a ping from the firewall to another host:
 * For the four lines in the Top Pane you will see the according lines
 * in the Middle Pane:
 *   El90x1 o
 * O El90x1
 * i El90x1
 *   El90x1 I
 *
 * Example for a packet traversing through the Firewall, first through
 * the inner side firewall module then through the outer side firewall module:
 * i  El90x1        El90x2
 *    El90x1 I      El90x2
 *    El90x1      o E190x2
 *    El90x1        E190x2 O
 *
 * 9.12.2002
 * Add new column with summary of FW-1 interface/direction
 *
 * 11.8.2003
 * Additional interpretation of field Chain Position.
 * Show the chain position in the interface list.
 * Support for new format of fw monitor file
 * written by option -u | -s for UUID/SUUID.
 * NOTICE: First paket will have UUID == 0 !
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 *
 * 30.5.2018
 * added inspection points "e" and "E"
 */

#include "config.h"


#include <epan/packet.h>
#include <epan/prefs.h>
#include <epan/etypes.h>

void proto_register_fw1(void);
void proto_reg_handoff_fw1(void);

/* Place FW1 summary in proto tree */
static bool fw1_summary_in_tree = true;
static bool fw1_with_uuid;
static bool fw1_iflist_with_chain;

static dissector_handle_t ethertype_handle;

/* Initialize the protocol and registered fields */
static int proto_fw1;
static int hf_fw1_direction;
static int hf_fw1_chain;
static int hf_fw1_interface;
static int hf_fw1_uuid;
static int hf_fw1_type;
static int hf_fw1_trailer;

/* Initialize the subtree pointers */
static int ett_fw1;

#define ETH_HEADER_SIZE 14

#define MAX_INTERFACES  20
static char     *p_interfaces[MAX_INTERFACES];
static int      interface_anzahl=0;

static void
fw1_init(void)
{
  interface_anzahl = 0;
}

static int
dissect_fw1(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    *fh_tree = NULL;
  char          direction;
  char  chain;
  char          *interface_name;
  uint32_t      iface_len = 10;
  wmem_strbuf_t *header;
  int           i;
  bool          found;
  static const char     fw1_header[] = "FW1 Monitor";
  ethertype_data_t ethertype_data;

  header = wmem_strbuf_create(pinfo->pool);
  wmem_strbuf_append(header, fw1_header);

  /* Make entries in Protocol column and Info column on summary display */
  col_set_str(pinfo->cinfo, COL_PROTOCOL, "FW1");
  col_clear(pinfo->cinfo, COL_INFO);

  /* fetch info to local variable */
  direction = tvb_get_uint8(tvb, 0);

  if (!fw1_iflist_with_chain)
    chain = ' ';
  else
    chain = tvb_get_uint8(tvb, 1);

  if (fw1_with_uuid)
    iface_len = 6;

  interface_name=tvb_get_stringzpad(pinfo->pool, tvb, 2, iface_len, ENC_ASCII|ENC_NA);

  /* Known interface name - if not, remember it */
  found=false;
  for (i=0; i<interface_anzahl; i++) {
    if ( strcmp(p_interfaces[i], interface_name) == 0 ) {
      found=true;
      break;
    }
  }
  if (!found && interface_anzahl < MAX_INTERFACES) {
    p_interfaces[interface_anzahl] = wmem_strdup(wmem_file_scope(), interface_name);
    interface_anzahl++;
  }

  /* display all interfaces always in the same order */
  for (i=0; i<interface_anzahl; i++) {
    if ( strcmp(p_interfaces[i], interface_name) == 0 ) {
      wmem_strbuf_append_printf(header, "  %c%c %s %c%c",
                                direction == 'i' ? 'i' : (direction == 'O' ? 'O' : (direction == 'E' ? 'E' :  ' ') ),
                                (direction == 'i' || direction == 'O' || direction == 'E') ? chain : ' ',
                                p_interfaces[i],
                                direction == 'I' ? 'I' : (direction == 'o' ? 'o' : (direction == 'e' ? 'e' :  ' ') ),
                                (direction == 'I' || direction == 'o' || direction == 'e') ? chain : ' '
        );
    } else {
      wmem_strbuf_append_printf(header, "    %s  ", p_interfaces[i]);
    }
  }

  col_add_str(pinfo->cinfo, COL_IF_DIR, wmem_strbuf_get_str(header) + sizeof(fw1_header) + 1);

  if (tree) {
    if (!fw1_summary_in_tree)
      /* Do not show the summary in Protocol Tree */
      ti = proto_tree_add_protocol_format(tree, proto_fw1, tvb, 0, ETH_HEADER_SIZE, "%s", fw1_header);
    else
      ti = proto_tree_add_protocol_format(tree, proto_fw1, tvb, 0, ETH_HEADER_SIZE, "%s", wmem_strbuf_get_str(header));

    /* create display subtree for the protocol */
    fh_tree = proto_item_add_subtree(ti, ett_fw1);

    proto_tree_add_item(fh_tree, hf_fw1_direction, tvb, 0, 1, ENC_ASCII);

    if (fw1_iflist_with_chain)
      proto_tree_add_item(fh_tree, hf_fw1_chain, tvb, 1, 1, ENC_ASCII);

    proto_tree_add_item(fh_tree, hf_fw1_interface, tvb, 2, iface_len, ENC_ASCII);

    if (fw1_with_uuid)
      proto_tree_add_item(fh_tree, hf_fw1_uuid, tvb, 8, 4, ENC_BIG_ENDIAN);
  }

  ethertype_data.etype = tvb_get_ntohs(tvb, 12);
  proto_tree_add_uint(fh_tree, hf_fw1_type, tvb, 12, 2, ethertype_data.etype);

  ethertype_data.payload_offset = ETH_HEADER_SIZE;
  ethertype_data.fh_tree = fh_tree;
  ethertype_data.trailer_id = hf_fw1_trailer;
  ethertype_data.fcs_len = 0;

  call_dissector_with_data(ethertype_handle, tvb, pinfo, tree, &ethertype_data);
  return tvb_captured_length(tvb);
}

void
proto_register_fw1(void)
{
  static hf_register_info hf[] = {
    { &hf_fw1_direction,
      { "Direction", "fw1.direction", FT_STRING, BASE_NONE, NULL, 0x0,
        NULL, HFILL }},

    { &hf_fw1_chain,
      { "Chain Position", "fw1.chain", FT_STRING, BASE_NONE, NULL, 0x0,
        NULL, HFILL }},

    { &hf_fw1_interface,
      { "Interface", "fw1.interface", FT_STRING, BASE_NONE, NULL, 0x0,
        NULL, HFILL }},

    { &hf_fw1_uuid,
      { "UUID", "fw1.uuid", FT_UINT32, BASE_DEC, NULL, 0x0,
        NULL, HFILL }},

    /* registered here but handled in ethertype.c */
    { &hf_fw1_type,
      { "Type", "fw1.type", FT_UINT16, BASE_HEX, VALS(etype_vals), 0x0,
        NULL, HFILL }},

    { &hf_fw1_trailer,
      { "Trailer", "fw1.trailer", FT_BYTES, BASE_NONE, NULL, 0x0,
        NULL, HFILL }
    }
  };
  /* Setup protocol subtree array */
  static int *ett[] = {
    &ett_fw1,
  };
  module_t *fw1_module;
  int       i;

  /* Register the protocol name and description */
  proto_fw1 = proto_register_protocol("Checkpoint FW-1", "FW-1", "fw1");
  /* Required function calls to register the header fields and subtrees used */
  proto_register_field_array(proto_fw1, hf, array_length(hf));
  proto_register_subtree_array(ett, array_length(ett));

  /* Register configuration preferences */
  fw1_module = prefs_register_protocol(proto_fw1, NULL);
  prefs_register_bool_preference(fw1_module, "summary_in_tree",
                                 "Show FireWall-1 summary in protocol tree",
                                 "Whether the FireWall-1 summary line should be shown in the protocol tree",
                                 &fw1_summary_in_tree);
  prefs_register_bool_preference(fw1_module, "with_uuid",
                                 "Monitor file includes UUID",
                                 "Whether the Firewall-1 monitor file includes UUID information",
                                 &fw1_with_uuid);
  prefs_register_bool_preference(fw1_module, "iflist_with_chain",
                                 "Interface list includes chain position",
                                 "Whether the interface list includes the chain position",
                                 &fw1_iflist_with_chain);

  register_dissector("fw1", dissect_fw1, proto_fw1);

  for (i=0; i<MAX_INTERFACES; i++) {
    p_interfaces[i] = NULL;
  }
  register_init_routine(fw1_init);
}

void
proto_reg_handoff_fw1(void)
{
    ethertype_handle = find_dissector_add_dependency("ethertype", proto_fw1);
}

/*
 * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 *
 * Local Variables:
 * c-basic-offset: 2
 * tab-width: 8
 * indent-tabs-mode: nil
 * End:
 *
 * ex: set shiftwidth=2 tabstop=8 expandtab:
 * :indentSize=2:tabSize=8:noTabs=true:
 */