epan/dissectors/packet-fw1.c

   1 /* packet-fw1.c
   2  * Routines for Ethernet header disassembly of FW1 "monitor" files
   3  * Copyright 2002,2003, Alfred Koebler <ako@icon.de>
   4  * Copyright 2018, Alfred Koebler <Alfred.Koebler2002ATgmx.de>
   5  *
   6  * Wireshark - Network traffic analyzer
   7  * By Alfred Koebler <ako@icon.de>
   8  * By Alfred Koebler <Alfred.Koebler2002ATgmx.de>
   9  * Copyright 2002,2003,2018 Alfred Koebler
  10  *
  11  * To use this dissector use the command line option
  12  * -o eth.interpret_as_fw1_monitor:true
  13  *
  14  * At the moment the way with the option is the best one.
  15  * A automatic way is not possible, because the file format isn't different
  16  * to the snoop file.
  17  *
  18  * With "fw monitor" it is possible to collect packets on several places.
  19  * The additional information:
  20  * - is it a incoming or outgoing packet
  21  * - is it before or after the firewall
  22  *   i  incoming before the firewall
  23  *   I  incoming after the firewall
  24  *   o  outcoming before the firewall
  25  *   O  outcoming after the firewall
  26  *   e  before VPN encryption
  27  *   E  after VPN encryption
  28  * - the name of the interface
  29  *
  30  * What's the problem ?
  31  * Think about one packet traveling across the firewall.
  32  * With wireshark you will see 4 lines in the Top Pane.
  33  * To analyze a problem it is helpful to see the additional information
  34  * in the protocol tree of the Middle Pane.
  35  *
  36  * The presentation of the summary line is designed in the following way:
  37  * Every time the next selected packet in the Top Pane includes a
  38  * "new" interface name the name is added to the list in the summary line.
  39  * The interface names are listed one after the other.
  40  * The position of the interface names didn't change.
  41  *
  42  * And who are the 4 places represented ?
  43  * The interface name represents the firewall module of the interface.
  44  * On the left side of the interface name is the interface module.
  45  * On the right side of the interface name is the "IP" module.
  46  *
  47  * Example for a ping from the firewall to another host:
  48  * For the four lines in the Top Pane you will see the according lines
  49  * in the Middle Pane:
  50  *   El90x1 o
  51  * O El90x1
  52  * i El90x1
  53  *   El90x1 I
  54  *
  55  * Example for a packet traversing through the Firewall, first through
  56  * the inner side firewall module then through the outer side firewall module:
  57  * i  El90x1        El90x2
  58  *    El90x1 I      El90x2
  59  *    El90x1      o E190x2
  60  *    El90x1        E190x2 O
  61  *
  62  * 9.12.2002
  63  * Add new column with summary of FW-1 interface/direction
  64  *
  65  * 11.8.2003
  66  * Additional interpretation of field Chain Position.
  67  * Show the chain position in the interface list.
  68  * Support for new format of fw monitor file
  69  * written by option -u | -s for UUID/SUUID.
  70  * NOTICE: First paket will have UUID == 0 !
  71  *
  72  * SPDX-License-Identifier: GPL-2.0-or-later
  73  *
  74  * 30.5.2018
  75  * added inspection points "e" and "E"
  76  */
  77
  78 #include "config.h"
  79
  80
  81 #include <epan/packet.h>
  82 #include <epan/prefs.h>
  83 #include <epan/etypes.h>
  84
  85 void proto_register_fw1(void);
  86 void proto_reg_handoff_fw1(void);
  87
  88 /* Place FW1 summary in proto tree */
  89 static bool fw1_summary_in_tree = true;
  90 static bool fw1_with_uuid;
  91 static bool fw1_iflist_with_chain;
  92
  93 static dissector_handle_t ethertype_handle;
  94
  95 /* Initialize the protocol and registered fields */
  96 static int proto_fw1;
  97 static int hf_fw1_direction;
  98 static int hf_fw1_chain;
  99 static int hf_fw1_interface;
 100 static int hf_fw1_uuid;
 101 static int hf_fw1_type;
 102 static int hf_fw1_trailer;
 103
 104 /* Initialize the subtree pointers */
 105 static int ett_fw1;
 106
 107 #define ETH_HEADER_SIZE 14
 108
 109 #define MAX_INTERFACES  20
 110 static char     *p_interfaces[MAX_INTERFACES];
 111 static int      interface_anzahl=0;
 112
 113 static void
 114 fw1_init(void)
 115 {
 116   interface_anzahl = 0;
 117 }
 118
 119 static int
 120 dissect_fw1(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
 121 {
 122   /* Set up structures needed to add the protocol subtree and manage it */
 123   proto_item    *ti;
 124   proto_tree    *fh_tree = NULL;
 125   char          direction;
 126   char  chain;
 127   char          *interface_name;
 128   uint32_t      iface_len = 10;
 129   wmem_strbuf_t *header;
 130   int           i;
 131   bool          found;
 132   static const char     fw1_header[] = "FW1 Monitor";
 133   ethertype_data_t ethertype_data;
 134
 135   header = wmem_strbuf_create(pinfo->pool);
 136   wmem_strbuf_append(header, fw1_header);
 137
 138   /* Make entries in Protocol column and Info column on summary display */
 139   col_set_str(pinfo->cinfo, COL_PROTOCOL, "FW1");
 140   col_clear(pinfo->cinfo, COL_INFO);
 141
 142   /* fetch info to local variable */
 143   direction = tvb_get_uint8(tvb, 0);
 144
 145   if (!fw1_iflist_with_chain)
 146     chain = ' ';
 147   else
 148     chain = tvb_get_uint8(tvb, 1);
 149
 150   if (fw1_with_uuid)
 151     iface_len = 6;
 152
 153   interface_name=tvb_get_stringzpad(pinfo->pool, tvb, 2, iface_len, ENC_ASCII|ENC_NA);
 154
 155   /* Known interface name - if not, remember it */
 156   found=false;
 157   for (i=0; i<interface_anzahl; i++) {
 158     if ( strcmp(p_interfaces[i], interface_name) == 0 ) {
 159       found=true;
 160       break;
 161     }
 162   }
 163   if (!found && interface_anzahl < MAX_INTERFACES) {
 164     p_interfaces[interface_anzahl] = wmem_strdup(wmem_file_scope(), interface_name);
 165     interface_anzahl++;
 166   }
 167
 168   /* display all interfaces always in the same order */
 169   for (i=0; i<interface_anzahl; i++) {
 170     if ( strcmp(p_interfaces[i], interface_name) == 0 ) {
 171       wmem_strbuf_append_printf(header, "  %c%c %s %c%c",
 172                                 direction == 'i' ? 'i' : (direction == 'O' ? 'O' : (direction == 'E' ? 'E' :  ' ') ),
 173                                 (direction == 'i' || direction == 'O' || direction == 'E') ? chain : ' ',
 174                                 p_interfaces[i],
 175                                 direction == 'I' ? 'I' : (direction == 'o' ? 'o' : (direction == 'e' ? 'e' :  ' ') ),
 176                                 (direction == 'I' || direction == 'o' || direction == 'e') ? chain : ' '
 177         );
 178     } else {
 179       wmem_strbuf_append_printf(header, "    %s  ", p_interfaces[i]);
 180     }
 181   }
 182
 183   col_add_str(pinfo->cinfo, COL_IF_DIR, wmem_strbuf_get_str(header) + sizeof(fw1_header) + 1);
 184
 185   if (tree) {
 186     if (!fw1_summary_in_tree)
 187       /* Do not show the summary in Protocol Tree */
 188       ti = proto_tree_add_protocol_format(tree, proto_fw1, tvb, 0, ETH_HEADER_SIZE, "%s", fw1_header);
 189     else
 190       ti = proto_tree_add_protocol_format(tree, proto_fw1, tvb, 0, ETH_HEADER_SIZE, "%s", wmem_strbuf_get_str(header));
 191
 192     /* create display subtree for the protocol */
 193     fh_tree = proto_item_add_subtree(ti, ett_fw1);
 194
 195     proto_tree_add_item(fh_tree, hf_fw1_direction, tvb, 0, 1, ENC_ASCII);
 196
 197     if (fw1_iflist_with_chain)
 198       proto_tree_add_item(fh_tree, hf_fw1_chain, tvb, 1, 1, ENC_ASCII);
 199
 200     proto_tree_add_item(fh_tree, hf_fw1_interface, tvb, 2, iface_len, ENC_ASCII);
 201
 202     if (fw1_with_uuid)
 203       proto_tree_add_item(fh_tree, hf_fw1_uuid, tvb, 8, 4, ENC_BIG_ENDIAN);
 204   }
 205
 206   ethertype_data.etype = tvb_get_ntohs(tvb, 12);
 207   proto_tree_add_uint(fh_tree, hf_fw1_type, tvb, 12, 2, ethertype_data.etype);
 208
 209   ethertype_data.payload_offset = ETH_HEADER_SIZE;
 210   ethertype_data.fh_tree = fh_tree;
 211   ethertype_data.trailer_id = hf_fw1_trailer;
 212   ethertype_data.fcs_len = 0;
 213
 214   call_dissector_with_data(ethertype_handle, tvb, pinfo, tree, &ethertype_data);
 215   return tvb_captured_length(tvb);
 216 }
 217
 218 void
 219 proto_register_fw1(void)
 220 {
 221   static hf_register_info hf[] = {
 222     { &hf_fw1_direction,
 223       { "Direction", "fw1.direction", FT_STRING, BASE_NONE, NULL, 0x0,
 224         NULL, HFILL }},
 225
 226     { &hf_fw1_chain,
 227       { "Chain Position", "fw1.chain", FT_STRING, BASE_NONE, NULL, 0x0,
 228         NULL, HFILL }},
 229
 230     { &hf_fw1_interface,
 231       { "Interface", "fw1.interface", FT_STRING, BASE_NONE, NULL, 0x0,
 232         NULL, HFILL }},
 233
 234     { &hf_fw1_uuid,
 235       { "UUID", "fw1.uuid", FT_UINT32, BASE_DEC, NULL, 0x0,
 236         NULL, HFILL }},
 237
 238     /* registered here but handled in ethertype.c */
 239     { &hf_fw1_type,
 240       { "Type", "fw1.type", FT_UINT16, BASE_HEX, VALS(etype_vals), 0x0,
 241         NULL, HFILL }},
 242
 243     { &hf_fw1_trailer,
 244       { "Trailer", "fw1.trailer", FT_BYTES, BASE_NONE, NULL, 0x0,
 245         NULL, HFILL }
 246     }
 247   };
 248   /* Setup protocol subtree array */
 249   static int *ett[] = {
 250     &ett_fw1,
 251   };
 252   module_t *fw1_module;
 253   int       i;
 254
 255   /* Register the protocol name and description */
 256   proto_fw1 = proto_register_protocol("Checkpoint FW-1", "FW-1", "fw1");
 257   /* Required function calls to register the header fields and subtrees used */
 258   proto_register_field_array(proto_fw1, hf, array_length(hf));
 259   proto_register_subtree_array(ett, array_length(ett));
 260
 261   /* Register configuration preferences */
 262   fw1_module = prefs_register_protocol(proto_fw1, NULL);
 263   prefs_register_bool_preference(fw1_module, "summary_in_tree",
 264                                  "Show FireWall-1 summary in protocol tree",
 265                                  "Whether the FireWall-1 summary line should be shown in the protocol tree",
 266                                  &fw1_summary_in_tree);
 267   prefs_register_bool_preference(fw1_module, "with_uuid",
 268                                  "Monitor file includes UUID",
 269                                  "Whether the Firewall-1 monitor file includes UUID information",
 270                                  &fw1_with_uuid);
 271   prefs_register_bool_preference(fw1_module, "iflist_with_chain",
 272                                  "Interface list includes chain position",
 273                                  "Whether the interface list includes the chain position",
 274                                  &fw1_iflist_with_chain);
 275
 276   register_dissector("fw1", dissect_fw1, proto_fw1);
 277
 278   for (i=0; i<MAX_INTERFACES; i++) {
 279     p_interfaces[i] = NULL;
 280   }
 281   register_init_routine(fw1_init);
 282 }
 283
 284 void
 285 proto_reg_handoff_fw1(void)
 286 {
 287     ethertype_handle = find_dissector_add_dependency("ethertype", proto_fw1);
 288 }
 289
 290 /*
 291  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 292  *
 293  * Local Variables:
 294  * c-basic-offset: 2
 295  * tab-width: 8
 296  * indent-tabs-mode: nil
 297  * End:
 298  *
 299  * ex: set shiftwidth=2 tabstop=8 expandtab:
 300  * :indentSize=2:tabSize=8:noTabs=true:
 301  */