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openSAFETY: Disable heur dissector & scm bugfix 

- Bugfix for the SCM UDID, where the expert info was generated
   even if not necessary, and a SCM UDID consisting of zeroes was
   considered to be valid

 - Using the new method for enabling/disabling heuristic dissectors,
   this patch reworks the SIII dissection to perform exactly the
   same as the EPL dissection (which is the expected behavior)

Change-Id: Ide559c3e104b77818cef642b34e0076a7c5bd13d
Reviewed-on: https://code.wireshark.org/review/9735
Reviewed-by: Roland Knall <rknall@gmail.com>
Reviewed-by: Michael Mann <mmann78@netscape.net>
Petri-Dish: Michael Mann <mmann78@netscape.net>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Anders Broman <a.broman58@gmail.com>
This commit is contained in:
Roland Knall 2015-07-21 15:11:38 +02:00 committed by Anders Broman
parent b191f7e3da
commit c5bda791f2
1 changed files with 63 additions and 72 deletions
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135
epan/dissectors/packet-opensafety.c
View File

@ -266,13 +266,11 @@ static guint global_network_udp_port = OPENSAFETY_UDP_PORT;
static guint global_network_udp_port_sercosiii = OPENSAFETY_UDP_PORT_SIII;
static gboolean global_classify_transport = TRUE;
static gboolean global_enable_plk = TRUE;
static gboolean global_enable_udp = TRUE;
static gboolean global_enable_genudp = TRUE;
static gboolean global_enable_siii = TRUE;
static gboolean global_enable_pnio = FALSE;
static gboolean global_enable_mbtcp = TRUE;
static gboolean heuristic_siii_dissection_enabled = TRUE;
static heur_dissector_list_t heur_opensafety_spdo_subdissector_list;
static gboolean bDissector_Called_Once_Before = FALSE;
@ -287,12 +285,19 @@ static void
reset_dissector(void)
{
bDissector_Called_Once_Before = FALSE;
}
static void
setup_dissector(void)
{
heur_dtbl_entry_t * heur_entry = NULL;
reassembly_table_init(&os_reassembly_table, &addresses_reassembly_table_functions);
heur_entry = find_heur_dissector_by_unique_short_name("opensafety_sercosiii");
if ( heur_entry != NULL )
heuristic_siii_dissection_enabled = heur_entry->enabled;
}
static void
@ -1327,11 +1332,40 @@ dissect_opensafety_ssdo_message(tvbuff_t *message_tvb, packet_info *pinfo, proto
}
}
static void
opensafety_parse_scm_udid ( tvbuff_t* tvb, packet_info *pinfo, proto_tree *tree,
opensafety_packet_info *packet, guint offset )
{
proto_item * item = NULL;
gchar *scm_udid_test = NULL;
item = proto_tree_add_item(tree, hf_oss_snmt_udid, tvb, offset, 6, ENC_NA);
scm_udid_test = tvb_bytes_to_str_punct(wmem_packet_scope(), tvb, offset, 6, ':' );
if ( scm_udid_test != NULL && strlen ( scm_udid_test ) == 17 )
{
if ( g_strcmp0("00:00:00:00:00:00", scm_udid_test ) != 0 )
{
packet->payload.snmt->scm_udid = scm_udid_test;
if ( ( global_scm_udid_autoset == TRUE ) && ( memcmp ( global_scm_udid, scm_udid_test, 17 ) != 0 ) )
{
if ( local_scm_udid == NULL || memcmp ( local_scm_udid, scm_udid_test, 17 ) != 0 )
{
local_scm_udid = wmem_strdup(wmem_file_scope(), scm_udid_test );
expert_add_info_format(pinfo, item, &ei_scmudid_autodetected,
"Auto detected payload as SCM UDID [%s].", local_scm_udid);
}
}
}
}
}
static void
dissect_opensafety_snmt_message(tvbuff_t *message_tvb, packet_info *pinfo, proto_tree *opensafety_tree,
opensafety_packet_info *packet )
{
proto_item *item;
proto_tree *snmt_tree;
guint32 entry = 0;
guint16 addr, taddr, sdn;
@ -1448,21 +1482,7 @@ dissect_opensafety_snmt_message(tvbuff_t *message_tvb, packet_info *pinfo, proto
}
else if ( (db0 ^ OPENSAFETY_MSG_SNMT_EXT_SN_ASSIGNED_UDID_SCM) == 0 )
{
item = proto_tree_add_item(snmt_tree, hf_oss_snmt_udid, message_tvb, OSS_FRAME_POS_DATA + packet->frame.subframe1 + 1, 6, ENC_NA);
if ( global_scm_udid_autoset == TRUE )
{
packet->payload.snmt->scm_udid = wmem_strdup(wmem_packet_scope(),
tvb_bytes_to_str_punct(wmem_packet_scope(),
message_tvb, OSS_FRAME_POS_DATA + packet->frame.subframe1 + 1, 6, ':' ) );
if ( memcmp ( global_scm_udid, packet->payload.snmt->scm_udid, 17 ) != 0 )
{
local_scm_udid = wmem_strdup(wmem_file_scope(), packet->payload.snmt->scm_udid );
expert_add_info_format(pinfo, item, &ei_scmudid_autodetected,
"Auto detected payload as SCM UDID [%s].", packet->payload.snmt->scm_udid);
}
}
opensafety_parse_scm_udid ( message_tvb, pinfo, snmt_tree, packet, OSS_FRAME_POS_DATA + packet->frame.subframe1 + 1 );
}
else if ( ( db0 ^ OPENSAFETY_MSG_SNMT_EXT_SN_ASSIGNED_ADDITIONAL_SADR) == 0 )
{
@ -1500,17 +1520,7 @@ dissect_opensafety_snmt_message(tvbuff_t *message_tvb, packet_info *pinfo, proto
}
else if ( (db0 ^ OPENSAFETY_MSG_SNMT_EXT_SN_ASSIGN_UDID_SCM) == 0 )
{
item = proto_tree_add_item(snmt_tree, hf_oss_snmt_udid, message_tvb, OSS_FRAME_POS_DATA + packet->frame.subframe1 + 1, 6, ENC_NA);
packet->payload.snmt->scm_udid = wmem_strdup(wmem_packet_scope(),
tvb_bytes_to_str_punct(wmem_packet_scope(), message_tvb, OSS_FRAME_POS_DATA + packet->frame.subframe1 + 1, 6, ':' ) );
if ( ( global_scm_udid_autoset == TRUE ) && ( memcmp ( global_scm_udid, packet->payload.snmt->scm_udid, 17 ) != 0 ) )
{
local_scm_udid = wmem_strdup(wmem_file_scope(), packet->payload.snmt->scm_udid );
expert_add_info_format(pinfo, item, &ei_scmudid_autodetected,
"Auto detected payload as SCM UDID [%s].", packet->payload.snmt->scm_udid);
}
opensafety_parse_scm_udid ( message_tvb, pinfo, snmt_tree, packet, OSS_FRAME_POS_DATA + packet->frame.subframe1 + 1 );
}
else if ( ( db0 ^ OPENSAFETY_MSG_SNMT_EXT_ASSIGN_INIT_CT) == 0 )
{
@ -2189,9 +2199,6 @@ dissect_opensafety_epl(tvbuff_t *message_tvb, packet_info *pinfo, proto_tree *tr
proto_tree *epl_tree = NULL;
guint8 epl_msgtype = 0;
if ( ! global_enable_plk )
return result;
/* We will call the epl dissector by using call_dissector(). The epl dissector will then call
* the heuristic openSAFETY dissector again. By setting this information, we prevent a dissector
* loop */
@ -2222,40 +2229,35 @@ dissect_opensafety_epl(tvbuff_t *message_tvb, packet_info *pinfo, proto_tree *tr
return result;
}
static gboolean
dissect_opensafety_siii_udp(tvbuff_t *message_tvb, packet_info *pinfo, proto_tree *tree, void *data _U_ )
{
if ( ! global_enable_siii )
return FALSE;
return opensafety_package_dissector("openSAFETY/SercosIII UDP", "", FALSE, FALSE, 0,
message_tvb, pinfo, tree, OPENSAFETY_ACYCLIC_DATA );
}
static gboolean
dissect_opensafety_siii(tvbuff_t *message_tvb, packet_info *pinfo, proto_tree *tree, void *data _U_ )
{
gboolean result = FALSE;
gboolean udp = FALSE;
guint8 firstByte;
if ( ! global_enable_siii )
return result;
/* We can assume to have a SercosIII package, as the SercosIII dissector won't detect
* SercosIII-UDP packages, this is most likely SercosIII-over-ethernet */
/* The UDP dissection is not done by a heuristic, but rather by a normal dissector. But
* the customer may not expect, that if (s)he disables the SercosIII dissector, that the
* SercosIII UDP packages get still dissected. This will disable them as well. */
if ( ! heuristic_siii_dissection_enabled )
return FALSE;
/* We will call the SercosIII dissector by using call_dissector(). The SercosIII dissector will
* then call the heuristic openSAFETY dissector again. By setting this information, we prevent
* a dissector loop. */
if ( bDissector_Called_Once_Before == FALSE )
{
udp = pinfo->srcport == OPENSAFETY_UDP_PORT_SIII;
bDissector_Called_Once_Before = TRUE;
/* No frames can be sent in AT messages, therefore those get filtered right away */
firstByte = ( tvb_get_guint8(message_tvb, 0) << 1 );
if ( ( firstByte & 0x40 ) == 0x40 )
if ( udp || ( firstByte & 0x40 ) == 0x40 )
{
result = opensafety_package_dissector("openSAFETY/SercosIII", "sercosiii",
FALSE, FALSE, 0, message_tvb, pinfo, tree, OPENSAFETY_CYCLIC_DATA );
result = opensafety_package_dissector( "openSAFETY/SercosIII",
udp ? "" : "sercosiii",
FALSE, FALSE, 0, message_tvb, pinfo, tree,
udp ? OPENSAFETY_ACYCLIC_DATA : OPENSAFETY_CYCLIC_DATA );
}
bDissector_Called_Once_Before = FALSE;
}
@ -2268,9 +2270,6 @@ dissect_opensafety_pn_io(tvbuff_t *message_tvb, packet_info *pinfo, proto_tree *
{
gboolean result = FALSE;
if ( ! global_enable_pnio )
return result;
/* We will call the pn_io dissector by using call_dissector(). The epl dissector will then call
* the heuristic openSAFETY dissector again. By setting this information, we prevent a dissector
* loop */
@ -2335,7 +2334,7 @@ static void
apply_prefs ( void )
{
static dissector_handle_t opensafety_udpdata_handle;
static dissector_handle_t opensafety_sii_handle;
static dissector_handle_t opensafety_siii_handle;
static guint opensafety_udp_port_number;
static guint opensafety_udp_siii_port_number;
static gboolean opensafety_init = FALSE;
@ -2344,14 +2343,14 @@ apply_prefs ( void )
if ( !opensafety_init )
{
opensafety_udpdata_handle = find_dissector("opensafety_udpdata");
opensafety_sii_handle = find_dissector("opensafety_siii");
opensafety_siii_handle = find_dissector("opensafety_siii");
opensafety_init = TRUE;
}
else
{
/* Delete dissectors in preparation of a changed config setting */
dissector_delete_uint ("udp.port", opensafety_udp_port_number, opensafety_udpdata_handle);
dissector_delete_uint ("udp.port", opensafety_udp_siii_port_number, opensafety_sii_handle);
dissector_delete_uint ("udp.port", opensafety_udp_siii_port_number, opensafety_siii_handle);
}
@ -2365,7 +2364,7 @@ apply_prefs ( void )
/* Sercos III dissector does not handle UDP transport, has to be handled
* separately, everything else should be caught by the heuristic dissector
*/
dissector_add_uint("udp.port", opensafety_udp_siii_port_number, find_dissector("opensafety_siii_udp"));
dissector_add_uint("udp.port", opensafety_udp_siii_port_number, find_dissector("opensafety_siii"));
}
@ -2764,21 +2763,13 @@ proto_register_opensafety(void)
"Modbus/TCP words can be transcoded either big- or little endian. Default will be little endian",
&global_mbtcp_big_endian);
prefs_register_bool_preference(opensafety_module, "enable_plk",
"Enable heuristic dissection for Ethernet POWERLINK", "Enable heuristic dissection for Ethernet POWERLINK",
&global_enable_plk);
prefs_register_obsolete_preference(opensafety_module, "enable_plk");
prefs_register_obsolete_preference(opensafety_module, "enable_siii");
prefs_register_obsolete_preference(opensafety_module, "enable_pnio");
prefs_register_bool_preference(opensafety_module, "enable_udp",
"Enable heuristic dissection for openSAFETY over UDP encoded traffic", "Enable heuristic dissection for openSAFETY over UDP encoded traffic",
&global_enable_udp);
prefs_register_bool_preference(opensafety_module, "enable_genudp",
"Enable heuristic dissection for generic UDP encoded traffic", "Enable heuristic dissection for generic UDP encoded traffic",
&global_enable_genudp);
prefs_register_bool_preference(opensafety_module, "enable_siii",
"Enable heuristic dissection for SercosIII", "Enable heuristic dissection for SercosIII",
&global_enable_siii);
prefs_register_bool_preference(opensafety_module, "enable_pnio",
"Enable heuristic dissection for Profinet IO", "Enable heuristic dissection for Profinet IO",
&global_enable_pnio);
prefs_register_bool_preference(opensafety_module, "enable_mbtcp",
"Enable heuristic dissection for Modbus/TCP", "Enable heuristic dissection for Modbus/TCP",
&global_enable_mbtcp);
@ -2794,7 +2785,7 @@ proto_register_opensafety(void)
/* Registering default and ModBus/TCP dissector */
new_register_dissector("opensafety_udpdata", dissect_opensafety_udpdata, proto_opensafety );
new_register_dissector("opensafety_mbtcp", dissect_opensafety_mbtcp, proto_opensafety );
new_register_dissector("opensafety_siii_udp", dissect_opensafety_siii_udp, proto_opensafety );
new_register_dissector("opensafety_siii", dissect_opensafety_siii, proto_opensafety );
new_register_dissector("opensafety_pnio", dissect_opensafety_pn_io, proto_opensafety);
}