/* packet-vssmonitoring.c * Routines for dissection of VSS Monitoring timestamp and portstamp * * Copyright VSS Monitoring 2011 * * 20111205 - First edition by Sake Blok (sake.blok@SYN-bit.nl) * * Wireshark - Network traffic analyzer * By Gerald Combs * Copyright 1998 Gerald Combs * * SPDX-License-Identifier: GPL-2.0-or-later */ #include "config.h" #include #include #define VSS_NS_MASK 0x3fffffff #define CLKSRC_SHIFT 30 #define CLKSRC_LOCAL 0 #define CLKSRC_NTP 1 #define CLKSRC_GPS 2 #define CLKSRC_PTP 3 static const value_string clksrc_vals[] = { { CLKSRC_LOCAL, "Not Synced" }, { CLKSRC_NTP, "NTP" }, { CLKSRC_GPS, "GPS" }, { CLKSRC_PTP, "PTP" }, { 0, NULL } }; void proto_register_vssmonitoring(void); void proto_reg_handoff_vssmonitoring(void); static int proto_vssmonitoring; static int hf_vssmonitoring_time; static int hf_vssmonitoring_clksrc; static int hf_vssmonitoring_srcport; static gint ett_vssmonitoring; static gboolean vss_dissect_portstamping_only = FALSE; static gboolean vss_two_byte_portstamps = FALSE; static int dissect_vssmonitoring(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_) { proto_tree *ti = NULL; proto_tree *vssmonitoring_tree = NULL; guint offset = 0; guint trailer_len; guint portstamp_len = (vss_two_byte_portstamps) ? 2 : 1; nstime_t vssmonitoring_time; guint8 vssmonitoring_clksrc = 0; guint32 vssmonitoring_srcport = 0; struct tm *tmp; /* First get the length of the trailer */ trailer_len = tvb_reported_length(tvb); /* The trailer length is a sum (of any combination) of: * timestamp (8 bytes) * port stamp (1 or 2 bytes) * fcs (4 bytes) * * Our caller might pass in the trailer with FCS included, so we check for * a trailer with a length that includes one or more of a time stamp, * a 1-byte or 2-byte port stamp, and optionally an FCS. * * See * * https://web.archive.org/web/20160402091604/http://www.vssmonitoring.com/resources/feature-brief/Port-and-Time-Stamping.pdf * * which speaks of 2-byte port stamps as being for a "future release". * * Iris Packet Broker user manuals when VSS Monitoring was owned by * Tektronix also mentioned only a 1-byte port stamp. * * VSS Monitoring has since been acquired by NetScout. * Products released in 2019: * https://www.netscout.com/sites/default/files/2019-01/PFSPDS_002_EN-1803-nGenius-4200-Series-Packet-Flow-Switch.pdf * https://www.netscout.com/sites/default/files/2019-12/PFSPDS_003_EN-1901%20-%20nGenius%206010%20Packet%20Flow%20Switch.pdf * mention both Port Stamping and VLAN tagging under "traffic port tagging," * and also note separately that up to _256_ ports can be meshed together * across hardware to act as a single device. * * Products released in 2021: * https://www.netscout.com/sites/default/files/2021-07/PFSPDS_021_EN-2102%20-%20nGenius%207000%20Series%20Packet%20Flow%20Switches.pdf * https://www.netscout.com/sites/default/files/2021-07/PFSPDS_022_EN-2102%20-%20nGenius%205000%20Series%20Packet%20Flow%20Switches.pdf * mention only VLAN tagging, and not Port Stamping in the port tagging * feature section. * * VSS Monitoring has apparently never released a product with 2 byte * port stamps, and it seems going forward that port stamping is going * to be deprecrated in favor of VLAN tagging. * * So by default we'll assume port stamps are 1 byte, with 2 bytes * port stamps supported via preference (disabled by default.) * * This means a trailer length must not be more than 14 bytes, * and: * * must not be 3 modulo 4 (as it can't have both a 1-byte * and a 2-byte port stamp); * * can only be either 1 or 2 module 4, depending on the size * of port stamp we accept; * * if it's less than 8 bytes, must not be 0 modulo 4 (as * it must have a 1-byte or 2-byte port stamp, given that * it has no timestamp). */ if ( trailer_len > 12 + portstamp_len ) return 0; if ( (trailer_len & 3) != 0 && (trailer_len & 3) != portstamp_len ) return 0; /* * If we have a time stamp, check it for validity. */ if ( trailer_len >= 8 ) { vssmonitoring_time.secs = tvb_get_ntohl(tvb, offset); vssmonitoring_time.nsecs = tvb_get_ntohl(tvb, offset + 4); vssmonitoring_clksrc = (guint8)(((guint32)vssmonitoring_time.nsecs) >> CLKSRC_SHIFT); vssmonitoring_time.nsecs &= VSS_NS_MASK; /* Probably padding passed to this dissector (e.g., a 802.1Q tagged * packet where the minimum frame length was increased to account * for the tag, see IEEE Std 802.1Q-2014 G.2.3 "Minimum PDU Size") * FIXME: Should be made even stricter. */ if (vssmonitoring_time.secs == 0) return 0; /* The timestamp will be based on the uptime until the TAP is completely * booted, this takes about 60s, but use 1 hour to be sure */ if (vssmonitoring_time.secs > 3600) { /* Check whether the timestamp in the PCAP header and the VSS-Monitoring * differ less than 30 days, otherwise, this might not be a VSS-Monitoring * timestamp */ if ( vssmonitoring_time.secs > pinfo->abs_ts.secs ) { if ( vssmonitoring_time.secs - pinfo->abs_ts.secs > 2592000 ) /* 30 days */ return 0; } else { if ( pinfo->abs_ts.secs - vssmonitoring_time.secs > 2592000 ) /* 30 days */ return 0; } } /* The nanoseconds field should be less than 1000000000 */ if ( vssmonitoring_time.nsecs >= 1000000000 ) return 0; } else if (!vss_dissect_portstamping_only || (trailer_len & 3) == 0) { /* No timestamp, so we need a port stamp and be willing to accept * packets with port stamping but not time stamping. * * Unfortunately, the port stamp can be zero or any other value, so * this means that a one-byte or two-byte all-zero trailer that's just * padding can be misinterpreted as a VSS monitoring trailer, among * other false positives, so we disable that by default. */ return 0; } /* All systems are go, lets dissect the VSS-Monitoring trailer */ if (tree) { ti = proto_tree_add_item(tree, proto_vssmonitoring, tvb, 0, (trailer_len & 0xb), ENC_NA); vssmonitoring_tree = proto_item_add_subtree(ti, ett_vssmonitoring); } /* Do we have a timestamp? */ if ( trailer_len >= 8 ) { if (tree) { proto_tree_add_time(vssmonitoring_tree, hf_vssmonitoring_time, tvb, offset, 8, &vssmonitoring_time); proto_tree_add_uint(vssmonitoring_tree, hf_vssmonitoring_clksrc, tvb, offset + 4, 1, vssmonitoring_clksrc); tmp = localtime(&vssmonitoring_time.secs); if (tmp) proto_item_append_text(ti, ", Timestamp: %02d:%02d:%02d.%09ld", tmp->tm_hour, tmp->tm_min, tmp->tm_sec,(long)vssmonitoring_time.nsecs); else proto_item_append_text(ti, ", Timestamp: "); } offset += 8; } /* Do we have a port stamp? */ if ( (trailer_len & 3) == portstamp_len) { if (tree) { proto_tree_add_item_ret_uint(vssmonitoring_tree, hf_vssmonitoring_srcport, tvb, offset, portstamp_len, ENC_BIG_ENDIAN, &vssmonitoring_srcport); proto_item_append_text(ti, ", Source Port: %d", vssmonitoring_srcport); } offset += portstamp_len; } return offset; } void proto_register_vssmonitoring(void) { static hf_register_info hf[] = { { &hf_vssmonitoring_time, { "Time Stamp", "vssmonitoring.time", FT_ABSOLUTE_TIME, ABSOLUTE_TIME_LOCAL, NULL, 0x0, "VSS Monitoring Time Stamp", HFILL }}, { &hf_vssmonitoring_clksrc, { "Clock Source", "vssmonitoring.clksrc", FT_UINT8, BASE_DEC, VALS(clksrc_vals), 0x0, "VSS Monitoring Clock Source", HFILL }}, { &hf_vssmonitoring_srcport, { "Src Port", "vssmonitoring.srcport", FT_UINT16, BASE_DEC, NULL, 0x0, "VSS Monitoring Source Port", HFILL }} }; static gint *ett[] = { &ett_vssmonitoring }; module_t *vssmonitoring_module; proto_vssmonitoring = proto_register_protocol("VSS Monitoring Ethernet trailer", "VSS Monitoring", "vssmonitoring"); proto_register_field_array(proto_vssmonitoring, hf, array_length(hf)); proto_register_subtree_array(ett, array_length(ett)); vssmonitoring_module = prefs_register_protocol(proto_vssmonitoring, NULL); prefs_register_obsolete_preference(vssmonitoring_module, "use_heuristics"); prefs_register_bool_preference(vssmonitoring_module, "dissect_portstamping_only", "Dissect trailers with only port stamping", "Whether the VSS Monitoring dissector should attempt to dissect trailers with no timestamp, only port stamping. Note that this can result in a large number of false positives.", &vss_dissect_portstamping_only); prefs_register_bool_preference(vssmonitoring_module, "two_byte_portstamps", "Two byte port stamps", "Whether the VSS Monitoring dissector should assume that the port stamp is two bytes, instead of the standard one byte.", &vss_two_byte_portstamps); } void proto_reg_handoff_vssmonitoring(void) { heur_dissector_add("eth.trailer", dissect_vssmonitoring, "VSS Monitoring ethernet trailer", "vssmonitoring_eth", proto_vssmonitoring, HEURISTIC_ENABLE); } /* * 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: */