epan/dissectors/packet-sap.c

   1 /* packet-sap.c
   2  * Routines for sap packet dissection
   3  * RFC 2974
   4  *
   5  * Heikki Vatiainen <hessu@cs.tut.fi>
   6  *
   7  * $Id$
   8  *
   9  * Wireshark - Network traffic analyzer
  10  * By Gerald Combs <gerald@wireshark.org>
  11  * Copyright 1998 Gerald Combs
  12  *
  13  * Copied from packet-tftp.c
  14  *
  15  * This program is free software; you can redistribute it and/or
  16  * modify it under the terms of the GNU General Public License
  17  * as published by the Free Software Foundation; either version 2
  18  * of the License, or (at your option) any later version.
  19  *
  20  * This program is distributed in the hope that it will be useful,
  21  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  22  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  23  * GNU General Public License for more details.
  24  *
  25  * You should have received a copy of the GNU General Public License
  26  * along with this program; if not, write to the Free Software
  27  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  28  */
  29
  30 #include "config.h"
  31
  32 #include <glib.h>
  33 #include <epan/packet.h>
  34 #include <epan/expert.h>
  35
  36 #define UDP_PORT_SAP    9875
  37
  38 #define MCAST_SAP_VERSION_MASK 0xE0 /* 3 bits for  SAP version*/
  39 #define MCAST_SAP_VERSION_SHIFT 5   /* Right shift 5 bits to get the version */
  40 #define MCAST_SAP_VER0 0            /* Version 0 */
  41 #define MCAST_SAP_VER1PLUS 1        /* Version 1 or later */
  42 static const value_string mcast_sap_ver[] = {
  43     { MCAST_SAP_VER0,     "SAPv0"},
  44     { MCAST_SAP_VER1PLUS, "SAPv1 or later"},
  45     { 0,                  NULL}
  46 };
  47
  48 static const true_false_string mcast_sap_address_type = {"IPv6", "IPv4"};
  49 static const true_false_string mcast_sap_message_type = { "Deletion", "Announcement"};
  50 static const true_false_string mcast_sap_crypt_type = { "Payload encrypted", "Payload not encrypted "};
  51 static const true_false_string mcast_sap_comp_type = { "Payload compressed", "Payload not compressed"};
  52
  53 static const value_string mcast_sap_auth_ver[] = {
  54     { 1, "SAP authentication header v1"},
  55     { 0,                  NULL}
  56 };
  57
  58 static const true_false_string mcast_sap_auth_pad = {
  59     "Authentication subheader padded to 32 bits",
  60     "No padding required for the authentication subheader"
  61 };
  62
  63 #define MCAST_SAP_AUTH_TYPE_MASK 0x0F /* 4 bits for the type of the authentication header */
  64 #define MCAST_SAP_AUTH_TYPE_PGP 0
  65 #define MCAST_SAP_AUTH_TYPE_CMS 1
  66 static const value_string mcast_sap_auth_type[] = {
  67     { MCAST_SAP_AUTH_TYPE_PGP,  "PGP"},
  68     { MCAST_SAP_AUTH_TYPE_CMS,  "CMS"},
  69     { 0,                   NULL}
  70 };
  71
  72 #define MCAST_SAP_BIT_A 0x10 /* Address type: 0 IPv4, 1 IPv6 */
  73 #define MCAST_SAP_BIT_R 0x08 /* Reserved: Must be 0 */
  74 #define MCAST_SAP_BIT_T 0x04 /* Message Type: 0 announcement, 1 deletion */
  75 #define MCAST_SAP_BIT_E 0x02 /* Encryption Bit: 1 payload encrypted */
  76 #define MCAST_SAP_BIT_C 0x01 /* Compressed Bit: 1 payload zlib compressed */
  77
  78 #define MCAST_SAP_AUTH_BIT_P 0x10 /* Padding required for the authentication header */
  79
  80
  81 static int proto_sap = -1;
  82 static int hf_sap_flags = -1;
  83 static int hf_sap_flags_v = -1;
  84 static int hf_sap_flags_a = -1;
  85 static int hf_sap_flags_r = -1;
  86 static int hf_sap_flags_t = -1;
  87 static int hf_sap_flags_e = -1;
  88 static int hf_sap_flags_c = -1;
  89 static int hf_auth_data = -1;
  90 static int hf_auth_flags = -1;
  91 static int hf_auth_flags_v = -1;
  92 static int hf_auth_flags_p = -1;
  93 static int hf_auth_flags_t = -1;
  94 /* Generated from convert_proto_tree_add_text.pl */
  95 static int hf_sap_auth_len = -1;
  96 static int hf_sap_originating_source_ipv4 = -1;
  97 static int hf_sap_auth_data_padding = -1;
  98 static int hf_sap_auth_subheader = -1;
  99 static int hf_sap_originating_source_ipv6 = -1;
 100 static int hf_sap_message_identifier_hash = -1;
 101 static int hf_sap_auth_data_padding_len = -1;
 102 static int hf_sap_payload_type = -1;
 103
 104 static gint ett_sap = -1;
 105 static gint ett_sap_flags = -1;
 106 static gint ett_sap_auth = -1;
 107 static gint ett_sap_authf = -1;
 108
 109 static expert_field ei_sap_compressed_and_encrypted = EI_INIT;
 110 static expert_field ei_sap_encrypted = EI_INIT;
 111 static expert_field ei_sap_compressed = EI_INIT;
 112 /* Generated from convert_proto_tree_add_text.pl */
 113 static expert_field ei_sap_bogus_authentication_or_pad_length = EI_INIT;
 114
 115 static dissector_handle_t sdp_handle;
 116
 117 static void
 118 dissect_sap(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 119 {
 120     int offset = 0;
 121     int sap_version, is_ipv6, is_del, is_enc, is_comp, addr_len;
 122     guint8 vers_flags;
 123     guint8 auth_len;
 124     guint8 auth_flags;
 125     tvbuff_t *next_tvb;
 126
 127     proto_item *si, *sif;
 128     proto_tree *sap_tree = NULL, *sap_flags_tree;
 129
 130     col_set_str(pinfo->cinfo, COL_PROTOCOL, "SAP");
 131     col_clear(pinfo->cinfo, COL_INFO);
 132
 133     vers_flags = tvb_get_guint8(tvb, offset);
 134     is_ipv6 = vers_flags&MCAST_SAP_BIT_A;
 135     is_del = vers_flags&MCAST_SAP_BIT_T;
 136     is_enc = vers_flags&MCAST_SAP_BIT_E;
 137     is_comp = vers_flags&MCAST_SAP_BIT_C;
 138
 139     sap_version = (vers_flags&MCAST_SAP_VERSION_MASK)>>MCAST_SAP_VERSION_SHIFT;
 140     addr_len = (is_ipv6) ? (int)sizeof(struct e_in6_addr) : 4;
 141
 142     col_add_fstr(pinfo->cinfo, COL_INFO, "%s (v%u)",
 143                             (is_del) ? "Deletion" : "Announcement", sap_version);
 144
 145     if (tree) {
 146         si = proto_tree_add_item(tree, proto_sap, tvb, offset, -1, ENC_NA);
 147         sap_tree = proto_item_add_subtree(si, ett_sap);
 148
 149         sif = proto_tree_add_item(sap_tree, hf_sap_flags, tvb, offset, 1, ENC_NA);
 150         sap_flags_tree = proto_item_add_subtree(sif, ett_sap_flags);
 151         proto_tree_add_item(sap_flags_tree, hf_sap_flags_v, tvb, offset, 1, ENC_NA);
 152         proto_tree_add_item(sap_flags_tree, hf_sap_flags_a, tvb, offset, 1, ENC_NA);
 153         proto_tree_add_item(sap_flags_tree, hf_sap_flags_r, tvb, offset, 1, ENC_NA);
 154         proto_tree_add_item(sap_flags_tree, hf_sap_flags_t, tvb, offset, 1, ENC_NA);
 155         proto_tree_add_item(sap_flags_tree, hf_sap_flags_e, tvb, offset, 1, ENC_NA);
 156         proto_tree_add_item(sap_flags_tree, hf_sap_flags_c, tvb, offset, 1, ENC_NA);
 157     }
 158
 159     offset++;
 160
 161     auth_len = tvb_get_guint8(tvb, offset);
 162     proto_tree_add_item(sap_tree, hf_sap_auth_len, tvb, offset, 1, ENC_NA);
 163     offset++;
 164
 165     proto_tree_add_item(sap_tree, hf_sap_message_identifier_hash, tvb, offset, 2, ENC_BIG_ENDIAN);
 166     offset +=2;
 167
 168     if (is_ipv6)
 169         proto_tree_add_item(sap_tree, hf_sap_originating_source_ipv4, tvb, offset, addr_len, ENC_BIG_ENDIAN);
 170     else
 171         proto_tree_add_item(sap_tree, hf_sap_originating_source_ipv6, tvb, offset, addr_len, ENC_BIG_ENDIAN);
 172     offset += addr_len;
 173
 174     /* Authentication data lives in its own subtree */
 175     if (auth_len > 0) {
 176         guint32 auth_data_len;
 177         proto_item *sdi, *sai;
 178         proto_tree *sa_tree, *saf_tree;
 179         int has_pad;
 180         guint8 pad_len = 0;
 181
 182         auth_data_len = (guint32)(auth_len * sizeof(guint32));
 183
 184         sdi = proto_tree_add_item(sap_tree, hf_auth_data, tvb, offset, auth_data_len, ENC_NA);
 185         sa_tree = proto_item_add_subtree(sdi, ett_sap_auth);
 186
 187         auth_flags = tvb_get_guint8(tvb, offset);
 188         sai = proto_tree_add_item(sa_tree, hf_auth_flags, tvb, offset, 1, ENC_NA);
 189         saf_tree = proto_item_add_subtree(sai, ett_sap_authf);
 190         proto_tree_add_item(saf_tree, hf_auth_flags_v, tvb, offset, 1, ENC_NA);
 191         proto_tree_add_item(saf_tree, hf_auth_flags_p, tvb, offset, 1, ENC_NA);
 192         proto_tree_add_item(saf_tree, hf_auth_flags_t, tvb, offset, 1, ENC_NA);
 193
 194         has_pad = auth_flags&MCAST_SAP_AUTH_BIT_P;
 195         if (has_pad) {
 196             pad_len = tvb_get_guint8(tvb, offset+auth_data_len-1);
 197         }
 198
 199         if ((int) auth_data_len - pad_len - 1 < 0) {
 200             expert_add_info_format(pinfo, sai, &ei_sap_bogus_authentication_or_pad_length,
 201                                         "Bogus authentication length (%d) or pad length (%d)", auth_len, pad_len);
 202             return;
 203         }
 204
 205
 206         proto_tree_add_item(sa_tree, hf_sap_auth_subheader, tvb, offset+1, auth_data_len-pad_len-1, ENC_NA);
 207         if (has_pad) {
 208             proto_tree_add_item(sa_tree, hf_sap_auth_data_padding_len, tvb, offset+auth_data_len-1, 1, ENC_NA);
 209             proto_tree_add_item(sa_tree, hf_sap_auth_data_padding, tvb, offset+auth_data_len-pad_len, pad_len, ENC_NA);
 210         }
 211
 212         offset += auth_data_len;
 213     }
 214
 215     if (is_enc || is_comp) {
 216         expert_field *mangle;
 217         if (is_enc && is_comp)
 218             mangle = &ei_sap_compressed_and_encrypted;
 219         else if (is_enc)
 220             mangle = &ei_sap_encrypted;
 221         else
 222             mangle = &ei_sap_compressed;
 223
 224         proto_tree_add_expert(sap_tree, pinfo, mangle, tvb, offset, -1);
 225         return;
 226     }
 227
 228     if (tree) {
 229         /* Do we have the optional payload type aka. MIME content specifier */
 230         if (tvb_strneql(tvb, offset, "v=", strlen("v="))) {
 231             gint remaining_len;
 232             guint32 pt_len;
 233             int pt_string_len;
 234             guint8* pt_str;
 235
 236             remaining_len = tvb_length_remaining(tvb, offset);
 237             if (remaining_len == 0) {
 238                 /*
 239                     * "tvb_strneql()" failed because there was no
 240                     * data left in the packet.
 241                     *
 242                     * Set the remaining length to 1, so that
 243                     * we throw the appropriate exception in
 244                     * "tvb_get_ptr()", rather than displaying
 245                     * the payload type.
 246                     */
 247                 remaining_len = 1;
 248             }
 249
 250             pt_string_len = tvb_strnlen(tvb, offset, remaining_len);
 251             if (pt_string_len == -1) {
 252                 /*
 253                  * We didn't find a terminating '\0'; run to the
 254                  * end of the buffer.
 255                  */
 256                 pt_string_len = remaining_len;
 257                 pt_len = pt_string_len;
 258             } else {
 259                 /*
 260                  * Include the '\0' in the total item length.
 261                  */
 262                 pt_len = pt_string_len + 1;
 263             }
 264
 265             pt_str = tvb_get_string(wmem_packet_scope(), tvb, offset, pt_string_len);
 266             proto_tree_add_string_format_value(sap_tree, hf_sap_payload_type, tvb, offset, pt_len,
 267                 pt_str, "%.*s", pt_string_len, pt_str);
 268             offset += pt_len;
 269         }
 270     }
 271
 272     /* Done with SAP */
 273     next_tvb = tvb_new_subset_remaining(tvb, offset);
 274     call_dissector(sdp_handle, next_tvb, pinfo, tree);
 275 }
 276
 277 void proto_register_sap(void)
 278 {
 279
 280     static hf_register_info hf[] = {
 281     { &hf_sap_flags,
 282         { "Flags",         "sap.flags",
 283         FT_UINT8, BASE_HEX, NULL, 0x0,
 284         "Bits in the beginning of the SAP header", HFILL }},
 285
 286     { &hf_sap_flags_v,
 287         { "Version Number",         "sap.flags.v",
 288         FT_UINT8, BASE_DEC, VALS(mcast_sap_ver), MCAST_SAP_VERSION_MASK,
 289         "3 bit version field in the SAP header", HFILL }},
 290
 291     { &hf_sap_flags_a,
 292         { "Address Type",           "sap.flags.a",
 293         FT_BOOLEAN, 8, TFS(&mcast_sap_address_type), MCAST_SAP_BIT_A,
 294         "Originating source address type", HFILL }},
 295
 296     { &hf_sap_flags_r,
 297         { "Reserved",               "sap.flags.r",
 298         FT_BOOLEAN, 8, TFS(&tfs_set_notset), MCAST_SAP_BIT_R,
 299         NULL, HFILL }},
 300
 301     { &hf_sap_flags_t,
 302         { "Message Type",           "sap.flags.t",
 303         FT_BOOLEAN, 8, TFS(&mcast_sap_message_type), MCAST_SAP_BIT_T,
 304         "Announcement type", HFILL }},
 305
 306     { &hf_sap_flags_e,
 307         { "Encryption Bit",         "sap.flags.e",
 308         FT_BOOLEAN, 8, TFS(&mcast_sap_crypt_type), MCAST_SAP_BIT_E,
 309         NULL, HFILL }},
 310
 311     { &hf_sap_flags_c,
 312         { "Compression Bit",         "sap.flags.c",
 313         FT_BOOLEAN, 8, TFS(&mcast_sap_comp_type), MCAST_SAP_BIT_C,
 314         NULL, HFILL }},
 315
 316     { &hf_auth_data,
 317         { "Authentication data",     "sap.auth",
 318         FT_NONE, BASE_NONE, NULL, 0x0,
 319         NULL, HFILL }},
 320
 321     { &hf_auth_flags,
 322         { "Authentication data flags", "sap.auth.flags",
 323         FT_UINT8, BASE_HEX, NULL, 0x0,
 324         NULL, HFILL }},
 325
 326     { &hf_auth_flags_v,
 327         { "Version Number",         "sap.auth.flags.v",
 328         FT_UINT8, BASE_DEC, VALS(mcast_sap_auth_ver), MCAST_SAP_VERSION_MASK,
 329         NULL, HFILL }},
 330
 331     { &hf_auth_flags_p,
 332         { "Padding Bit",            "sap.auth.flags.p",
 333         FT_BOOLEAN, 8, TFS(&mcast_sap_auth_pad), MCAST_SAP_AUTH_BIT_P,
 334         NULL, HFILL }},
 335
 336     { &hf_auth_flags_t,
 337         { "Authentication Type",         "sap.auth.flags.t",
 338         FT_UINT8, BASE_DEC, VALS(mcast_sap_auth_type), MCAST_SAP_AUTH_TYPE_MASK,
 339         NULL, HFILL }},
 340
 341         /* Generated from convert_proto_tree_add_text.pl */
 342         { &hf_sap_auth_len, { "Authentication Length", "sap.auth.len", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL }},
 343         { &hf_sap_message_identifier_hash, { "Message Identifier Hash", "sap.message_identifier_hash", FT_UINT16, BASE_HEX, NULL, 0x0, NULL, HFILL }},
 344         { &hf_sap_originating_source_ipv4, { "Originating Source", "sap.originating_source", FT_IPv4, BASE_NONE, NULL, 0x0, NULL, HFILL }},
 345         { &hf_sap_originating_source_ipv6, { "Originating Source", "sap.originating_source", FT_IPv6, BASE_NONE, NULL, 0x0, NULL, HFILL }},
 346         { &hf_sap_auth_subheader, { "Authentication subheader", "sap.auth.subheader", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL }},
 347         { &hf_sap_auth_data_padding, { "Authentication data padding", "sap.auth.data_padding", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL }},
 348         { &hf_sap_auth_data_padding_len, { "Authentication data pad count (bytes)", "sap.auth.data_padding.len", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL }},
 349         { &hf_sap_payload_type, { "Payload type", "sap.payload_type", FT_STRING, BASE_NONE, NULL, 0x0, NULL, HFILL }},
 350
 351     };
 352     static gint *ett[] = {
 353         &ett_sap,
 354         &ett_sap_flags,
 355         &ett_sap_auth,
 356         &ett_sap_authf,
 357     };
 358
 359     static ei_register_info ei[] = {
 360         { &ei_sap_compressed_and_encrypted, { "sap.compressed_and_encrypted", PI_UNDECODED, PI_WARN, "The rest of the packet is compressed and encrypted", EXPFILL }},
 361         { &ei_sap_encrypted, { "sap.encrypted", PI_UNDECODED, PI_WARN, "The rest of the packet is encrypted", EXPFILL }},
 362         { &ei_sap_compressed, { "sap.compressed", PI_UNDECODED, PI_WARN, "The rest of the packet is compressed", EXPFILL }},
 363
 364         /* Generated from convert_proto_tree_add_text.pl */
 365         { &ei_sap_bogus_authentication_or_pad_length, { "sap.bogus_authentication_or_pad_length", PI_PROTOCOL, PI_WARN, "Bogus authentication length", EXPFILL }},
 366     };
 367
 368     expert_module_t* expert_sap;
 369
 370     proto_sap = proto_register_protocol("Session Announcement Protocol", "SAP", "sap");
 371
 372     proto_register_field_array(proto_sap, hf, array_length(hf));
 373     proto_register_subtree_array(ett, array_length(ett));
 374     expert_sap = expert_register_protocol(proto_sap);
 375     expert_register_field_array(expert_sap, ei, array_length(ei));
 376 }
 377
 378 void
 379 proto_reg_handoff_sap(void)
 380 {
 381     dissector_handle_t sap_handle;
 382
 383     sap_handle = create_dissector_handle(dissect_sap, proto_sap);
 384     dissector_add_uint("udp.port", UDP_PORT_SAP, sap_handle);
 385
 386     /*
 387      * Get a handle for the SDP dissector.
 388      */
 389     sdp_handle = find_dissector("sdp");
 390 }