epan/dissectors/packet-isis.c

   1 /* packet-isis.c
   2  * Routines for ISO/OSI network and transport protocol packet disassembly, core
   3  * bits.
   4  *
   5  * Stuart Stanley <stuarts@mxmail.net>
   6  *
   7  * Wireshark - Network traffic analyzer
   8  * By Gerald Combs <gerald@wireshark.org>
   9  * Copyright 1998 Gerald Combs
  10  *
  11  * SPDX-License-Identifier: GPL-2.0-or-later
  12  */
  13
  14 #include "config.h"
  15
  16 #include <epan/packet.h>
  17 #include <epan/expert.h>
  18 #include <epan/nlpid.h>
  19 #include <epan/etypes.h>
  20 #include "packet-osi.h"
  21 #include "packet-isis.h"
  22
  23 void proto_register_isis(void);
  24 void proto_reg_handoff_isis(void);
  25
  26 static dissector_table_t isis_dissector_table;
  27
  28 /* isis base header */
  29 static int proto_isis;
  30
  31 static int hf_isis_irpd;
  32 static int hf_isis_header_length;
  33 static int hf_isis_version;
  34 static int hf_isis_system_id_length;
  35 static int hf_isis_type;
  36 static int hf_isis_type_reserved;
  37 static int hf_isis_version2;
  38 static int hf_isis_reserved;
  39 static int hf_isis_max_area_adr;
  40 int hf_isis_clv_key_id;
  41
  42 static int ett_isis;
  43
  44 static expert_field ei_isis_length_indicator_too_small;
  45 static expert_field ei_isis_version;
  46 static expert_field ei_isis_version2;
  47 static expert_field ei_isis_reserved;
  48 static expert_field ei_isis_type;
  49
  50 static dissector_handle_t isis_handle;
  51
  52 static const value_string isis_vals[] = {
  53     { ISIS_TYPE_L1_HELLO,  "L1 HELLO"},
  54     { ISIS_TYPE_L2_HELLO,  "L2 HELLO"},
  55     { ISIS_TYPE_PTP_HELLO, "P2P HELLO"},
  56     { ISIS_TYPE_L1_LSP,    "L1 LSP"},
  57     { ISIS_TYPE_L2_LSP,    "L2 LSP"},
  58     { ISIS_TYPE_L1_CSNP,   "L1 CSNP"},
  59     { ISIS_TYPE_L2_CSNP,   "L2 CSNP"},
  60     { ISIS_TYPE_L1_PSNP,   "L1 PSNP"},
  61     { ISIS_TYPE_L2_PSNP,   "L2 PSNP"},
  62     { 0,                   NULL}
  63 };
  64
  65 static int
  66 dissect_isis(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
  67 {
  68     proto_item *ti, *version_item, *version2_item, *reserved_item;
  69     proto_tree *isis_tree = NULL;
  70     int offset = 0;
  71     uint8_t isis_version, isis_version2, isis_reserved;
  72     uint8_t isis_type;
  73     isis_data_t subdissector_data;
  74
  75     col_set_str(pinfo->cinfo, COL_PROTOCOL, "ISIS");
  76     col_clear(pinfo->cinfo, COL_INFO);
  77
  78     ti = proto_tree_add_item(tree, proto_isis, tvb, 0, -1, ENC_NA);
  79     isis_tree = proto_item_add_subtree(ti, ett_isis);
  80
  81     proto_tree_add_item(isis_tree, hf_isis_irpd, tvb, offset, 1, ENC_BIG_ENDIAN );
  82     offset += 1;
  83
  84     subdissector_data.header_length = tvb_get_uint8(tvb, offset);
  85     subdissector_data.header_length_item =
  86         proto_tree_add_uint(isis_tree, hf_isis_header_length, tvb,
  87             offset, 1, subdissector_data.header_length );
  88     offset += 1;
  89     if (subdissector_data.header_length < 8) {
  90         /* Not large enough to include the part of the header that
  91            we dissect here. */
  92         expert_add_info(pinfo, subdissector_data.header_length_item, &ei_isis_length_indicator_too_small);
  93         return tvb_captured_length(tvb);
  94     }
  95     subdissector_data.ei_bad_header_length = &ei_isis_length_indicator_too_small;
  96
  97     isis_version = tvb_get_uint8(tvb, offset);
  98     version_item = proto_tree_add_uint(isis_tree, hf_isis_version, tvb,
  99             offset, 1, isis_version );
 100     if (isis_version != ISIS_REQUIRED_VERSION){
 101         expert_add_info(pinfo, version_item, &ei_isis_version);
 102     }
 103     offset += 1;
 104
 105     subdissector_data.system_id_len = tvb_get_uint8(tvb, offset);
 106     proto_tree_add_uint(isis_tree, hf_isis_system_id_length, tvb,
 107             offset, 1, subdissector_data.system_id_len );
 108     offset += 1;
 109
 110     proto_tree_add_item(isis_tree, hf_isis_type_reserved, tvb, offset, 1, ENC_BIG_ENDIAN );
 111
 112     isis_type = tvb_get_uint8(tvb, offset) & ISIS_TYPE_MASK;
 113     col_add_str(pinfo->cinfo, COL_INFO,
 114                 val_to_str ( isis_type, isis_vals, "Unknown (0x%x)" ) );
 115     proto_tree_add_item(isis_tree, hf_isis_type, tvb, offset, 1, ENC_BIG_ENDIAN );
 116     offset += 1;
 117
 118     isis_version2 = tvb_get_uint8(tvb, offset);
 119     version2_item = proto_tree_add_item(isis_tree, hf_isis_version2, tvb, offset, 1, ENC_BIG_ENDIAN );
 120     if (isis_version2 != 1) {
 121         expert_add_info(pinfo, version2_item, &ei_isis_version2);
 122     }
 123     offset += 1;
 124
 125     isis_reserved = tvb_get_uint8(tvb, offset);
 126     reserved_item = proto_tree_add_item(isis_tree, hf_isis_reserved, tvb, offset, 1, ENC_BIG_ENDIAN );
 127     if (isis_reserved != 0) {
 128         expert_add_info(pinfo, reserved_item, &ei_isis_reserved);
 129     }
 130     offset += 1;
 131
 132     proto_tree_add_item(isis_tree, hf_isis_max_area_adr, tvb, offset, 1, ENC_BIG_ENDIAN );
 133     offset += 1;
 134
 135     /*
 136      * Interpret the system ID length.
 137      */
 138     if (subdissector_data.system_id_len == 0)
 139         subdissector_data.system_id_len = 6;    /* zero means 6-octet ID field length */
 140     else if (subdissector_data.system_id_len == 255) {
 141         subdissector_data.system_id_len = 0;    /* 255 means null ID field */
 142         /* XXX - what about the LAN ID? */
 143     }
 144     /* XXX - otherwise, must be in the range 1 through 8 */
 145
 146     /*
 147      * We must pass the entire ISIS PDU to the dissector, as some
 148      * dissectors are for ISIS PDU types that might contain a
 149      * checksum TLV, and that checksum is over the entire PDU.
 150      */
 151     if (!dissector_try_uint_with_data(isis_dissector_table, isis_type, tvb,
 152                                 pinfo, tree, true, &subdissector_data))
 153     {
 154         proto_tree_add_expert(tree, pinfo, &ei_isis_type, tvb, offset, -1);
 155     }
 156     return tvb_captured_length(tvb);
 157 } /* dissect_isis */
 158
 159 void
 160 proto_register_isis(void)
 161 {
 162   static hf_register_info hf[] = {
 163     { &hf_isis_irpd,
 164       { "Intradomain Routing Protocol Discriminator",    "isis.irpd",
 165         FT_UINT8, BASE_HEX, VALS(nlpid_vals), 0x0, NULL, HFILL }},
 166
 167     { &hf_isis_header_length,
 168       { "Length Indicator", "isis.len", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL }},
 169
 170     { &hf_isis_version,
 171       { "Version/Protocol ID Extension", "isis.version", FT_UINT8,
 172          BASE_DEC, NULL, 0x0, NULL, HFILL }},
 173
 174     { &hf_isis_system_id_length,
 175       { "ID Length", "isis.sysid_len",
 176         FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL }},
 177
 178     { &hf_isis_type,
 179       { "PDU Type", "isis.type", FT_UINT8, BASE_DEC,
 180         VALS(isis_vals), ISIS_TYPE_MASK, NULL, HFILL }},
 181
 182     { &hf_isis_type_reserved,
 183       { "Reserved", "isis.type.reserved", FT_UINT8, BASE_HEX,
 184         NULL, ISIS_TYPE_RESERVED_MASK, NULL, HFILL }},
 185
 186     { &hf_isis_version2,
 187       { "Version", "isis.version2", FT_UINT8, BASE_DEC, NULL,
 188         0x0, NULL, HFILL }},
 189
 190     { &hf_isis_reserved,
 191       { "Reserved", "isis.reserved", FT_UINT8, BASE_DEC, NULL,
 192         0x0, NULL, HFILL }},
 193
 194     { &hf_isis_max_area_adr,
 195       { "Maximum Area Addresses", "isis.max_area_adr", FT_UINT8, BASE_DEC, NULL,
 196         0x0, "Maximum Area Addresses, 0 means 3", HFILL }},
 197
 198     { &hf_isis_clv_key_id,
 199       { "Key ID", "isis.clv.key_id", FT_UINT16, BASE_DEC, NULL,
 200         0x0, NULL, HFILL }},
 201   };
 202     /*
 203      * Note, we pull in the unknown CLV handler here, since it
 204      * is used by all ISIS packet types.
 205      */
 206     static int *ett[] = {
 207       &ett_isis,
 208     };
 209
 210     static ei_register_info ei[] = {
 211         { &ei_isis_length_indicator_too_small, { "isis.length_indicator_too_small", PI_MALFORMED, PI_ERROR, "ISIS length indicator value smaller than the fixed length header size", EXPFILL }},
 212         { &ei_isis_version, { "isis.version.unknown", PI_PROTOCOL, PI_WARN, "Unknown ISIS version", EXPFILL }},
 213         { &ei_isis_version2, { "isis.version2.notone", PI_PROTOCOL, PI_WARN, "Version must be 1", EXPFILL }},
 214         { &ei_isis_reserved, { "isis.reserved.notzero", PI_PROTOCOL, PI_WARN, "Reserved must be 0", EXPFILL }},
 215         { &ei_isis_type, { "isis.type.unknown", PI_PROTOCOL, PI_WARN, "Unknown ISIS packet type", EXPFILL }},
 216     };
 217
 218     expert_module_t* expert_isis;
 219
 220     proto_isis = proto_register_protocol(PROTO_STRING_ISIS, "ISIS", "isis");
 221     proto_register_field_array(proto_isis, hf, array_length(hf));
 222     proto_register_subtree_array(ett, array_length(ett));
 223     expert_isis = expert_register_protocol(proto_isis);
 224     expert_register_field_array(expert_isis, ei, array_length(ei));
 225
 226     isis_handle = register_dissector("isis", dissect_isis, proto_isis);
 227
 228     isis_dissector_table = register_dissector_table("isis.type",
 229                                 "ISIS Type", proto_isis, FT_UINT8, BASE_DEC);
 230 }
 231
 232 void
 233 proto_reg_handoff_isis(void)
 234 {
 235     dissector_add_uint("osinl.incl", NLPID_ISO10589_ISIS, isis_handle);
 236     dissector_add_uint("ethertype", ETHERTYPE_L2ISIS, isis_handle);
 237 }
 238
 239 /*
 240  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 241  *
 242  * Local variables:
 243  * c-basic-offset: 4
 244  * tab-width: 8
 245  * indent-tabs-mode: nil
 246  * End:
 247  *
 248  * vi: set shiftwidth=4 tabstop=8 expandtab:
 249  * :indentSize=4:tabSize=8:noTabs=true:
 250  */