Add Cisco Miscabling Protocol

Change-Id: Iab98bfeb2ab8aa2314e74ff4330b85e7f6533a48
Reviewed-on: https://code.wireshark.org/review/35116
Petri-Dish: Jörg Mayer <jmayer@loplof.de>
Tested-by: Petri Dish Buildbot
Reviewed-by: Jörg Mayer <jmayer@loplof.de>

2 files changed, 308 insertions, 0 deletions

diff --git a/epan/dissectors/CMakeLists.txt b/epan/dissectors/CMakeLists.txt
index 27039f81b9..766f529864 100644
--- a/epan/dissectors/CMakeLists.txt
+++ b/epan/dissectors/CMakeLists.txt
@@ -808,6 +808,7 @@ set(DISSECTOR_SRC
 	${CMAKE_CURRENT_SOURCE_DIR}/packet-cisco-erspan.c
 	${CMAKE_CURRENT_SOURCE_DIR}/packet-cisco-fp-mim.c
 	${CMAKE_CURRENT_SOURCE_DIR}/packet-cisco-marker.c
+	${CMAKE_CURRENT_SOURCE_DIR}/packet-cisco-mcp.c
 	${CMAKE_CURRENT_SOURCE_DIR}/packet-cisco-metadata.c
 	${CMAKE_CURRENT_SOURCE_DIR}/packet-cisco-oui.c
 	${CMAKE_CURRENT_SOURCE_DIR}/packet-cisco-sm.c
diff --git a/epan/dissectors/packet-cisco-mcp.c b/epan/dissectors/packet-cisco-mcp.c
new file mode 100644
index 0000000000..7082479bc8
--- /dev/null
+++ b/epan/dissectors/packet-cisco-mcp.c
@@ -0,0 +1,307 @@
+/* packet-cisco-mcp.c
+ * Routines for the disassembly of Cisco's MCP (Miscabling Protocol)
+ *
+ * Copyright 2019 Joerg Mayer (see AUTHORS file)
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+/*
+  TODO:
+  - Figure out the meaning of more types
+  - Figure out the hash calculation
+  - Display Value in TLV toplevel item where appropriate
+
+Specs: No specs available
+  No header
+  Sequence of TLVs of format
+  Type (1 byte)
+  Length (1 byte)
+  Value (Length bytes of Data)
+
+Patent:
+  http://www.freepatentsonline.com/20150124643.pdf
+Documentation:
+  https://www.cisco.com/c/en/us/solutions/collateral/data-center-virtualization/application-centric-infrastructure/white-paper-c11-737909.pdf
+  https://unofficialaciguide.com/2018/03/27/using-mcp-miscabling-protocol-for-aci/
+ */
+
+#include "config.h"
+
+#include <epan/packet.h>
+#include <epan/expert.h>
+#include <epan/to_str.h>
+#include <epan/cisco_pid.h>
+
+void proto_register_mcp(void);
+void proto_reg_handoff_mcp(void);
+
+static int proto_mcp = -1;
+/* TLV header */
+static int hf_mcp_tlv_type = -1;
+static int hf_mcp_tlv_length = -1;
+/* Values */
+static int hf_mcp_1 = -1;
+static int hf_mcp_switchid = -1;
+static int hf_mcp_3 = -1;
+static int hf_mcp_ifindex = -1;
+static int hf_mcp_timestamp = -1;
+static int hf_mcp_hmac = -1;
+// static int hf_mcp_end = -1;
+static int hf_mcp_unknown = -1;
+
+static expert_field ei_mcp_short_tlv = EI_INIT;
+static expert_field ei_mcp_trailing_bytes = EI_INIT;
+static expert_field ei_mcp_unexpected_tlv_length = EI_INIT;
+
+static gint ett_mcp = -1;
+static gint ett_mcp_tlv_header = -1;
+
+#define PROTO_SHORT_NAME "MCP"
+#define PROTO_LONG_NAME "Miscabling Protocol"
+
+typedef enum {
+	MCP_TYPE_1 = 1,		// Len=4, perhaps version or fabric-id
+	MCP_TYPE_SWITCHID = 2,	// Len=4,
+	MCP_TYPE_3 = 3,		// Len=12,
+	MCP_TYPE_IFINDEX = 4,	// Len=4,
+	MCP_TYPE_TIMESTAMP = 5,	// Len=4,
+	MCP_TYPE_HMAC = 6,	// Len=20, Guessing, possibly SHA1
+	MCP_TYPE_END = 7	// Len=0
+} mcp_type_t;
+
+static const value_string mcp_type_vals[] = {
+	{ MCP_TYPE_1,		"Unknown1"},
+	{ MCP_TYPE_SWITCHID,	"SwitchID"},
+	{ MCP_TYPE_3,		"Unknown3"},
+	{ MCP_TYPE_IFINDEX,	"IfIndex"},
+	{ MCP_TYPE_TIMESTAMP,	"Timestamp"},
+	{ MCP_TYPE_HMAC,	"HMAC?"},
+	{ MCP_TYPE_END,		"End"},
+
+	{ 0,	NULL }
+};
+
+static int
+dissect_mcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
+{
+	proto_item *ti;
+	proto_tree *mcp_tree;
+	proto_tree *tlv_tree;
+	guint32 offset = 0;
+	gboolean last = FALSE;
+	guint8 tlv_type;
+	guint16 tlv_length;
+	guint16 data_length = tvb_reported_length_remaining(tvb, offset);;
+	guint32 switchid, ifindex, timestamp;
+	gchar* timestamp_str;
+
+	col_set_str(pinfo->cinfo, COL_PROTOCOL, PROTO_SHORT_NAME);
+	col_set_str(pinfo->cinfo, COL_INFO, "");
+
+	ti = proto_tree_add_item(tree, proto_mcp, tvb, offset, -1,
+				 ENC_NA);
+	mcp_tree = proto_item_add_subtree(ti, ett_mcp);
+
+	/* No header whatsoever, just a plain sequence of TLVs */
+	while (offset < data_length && !last) {
+		if (data_length - offset < 2) {
+			proto_tree_add_expert_format(mcp_tree, pinfo, &ei_mcp_short_tlv, tvb,
+				offset, 4, "Too few bytes left for TLV (%u < 2)", data_length - offset);
+			break;
+		}
+		tlv_type = tvb_get_guint8(tvb, offset);
+		tlv_length = tvb_get_guint8(tvb, offset + 1);
+
+		tlv_tree = proto_tree_add_subtree_format(mcp_tree, tvb, offset, tlv_length + 2,
+			ett_mcp_tlv_header, NULL, "TLV length %d, type %d = %s",
+			tlv_length, tlv_type, val_to_str(tlv_type, mcp_type_vals, "Unknown (0x%02x)"));
+
+		proto_tree_add_uint(tlv_tree, hf_mcp_tlv_type, tvb, offset, 1, tlv_type);
+		offset += 1;
+
+		proto_tree_add_uint(tlv_tree, hf_mcp_tlv_length, tvb, offset, 1, tlv_length);
+		if (tlv_length > (data_length - (offset + 1))) {
+			proto_tree_add_expert_format(tlv_tree, pinfo, &ei_mcp_short_tlv, tvb,
+				offset, 1, "TLV length (%u) passes end of packet", tlv_length);
+			break;
+		}
+		offset += 1;
+
+		switch (tlv_type) {
+		case MCP_TYPE_1:
+			if (tlv_length == 4) {
+				proto_tree_add_item(tlv_tree, hf_mcp_1, tvb, offset, tlv_length, ENC_BIG_ENDIAN);
+			} else {
+				proto_tree_add_expert_format(mcp_tree, pinfo, &ei_mcp_unexpected_tlv_length, tvb,
+					offset, tlv_length, "Expected value length differs from seen length (%u != %u)",
+					4, tlv_length);
+			}
+			break;
+		case MCP_TYPE_SWITCHID:
+			if (tlv_length == 4) {
+				proto_tree_add_item_ret_uint(tlv_tree, hf_mcp_switchid, tvb, offset, tlv_length, ENC_BIG_ENDIAN, &switchid);
+				proto_item_append_text(tlv_tree, ": %u", switchid);
+				col_append_fstr(pinfo->cinfo, COL_INFO, "SwID/%u ", switchid);
+			} else {
+				proto_tree_add_expert_format(mcp_tree, pinfo, &ei_mcp_unexpected_tlv_length, tvb,
+					offset, tlv_length, "Expected value length differs from seen length (%u != %u)",
+					4, tlv_length);
+			}
+			break;
+		case MCP_TYPE_3:
+			proto_tree_add_item(tlv_tree, hf_mcp_3, tvb, offset, tlv_length, ENC_NA);
+			break;
+		case MCP_TYPE_IFINDEX:
+			if (tlv_length == 4) {
+				proto_tree_add_item_ret_uint(tlv_tree, hf_mcp_ifindex, tvb, offset, tlv_length, ENC_BIG_ENDIAN, &ifindex);
+				proto_item_append_text(tlv_tree, ": 0x%08x", ifindex);
+				col_append_fstr(pinfo->cinfo, COL_INFO, "ifIdx/0x%08x ", ifindex);
+			} else {
+				proto_tree_add_expert_format(mcp_tree, pinfo, &ei_mcp_unexpected_tlv_length, tvb,
+					offset, tlv_length, "Expected value length differs from seen length (%u != %u)",
+					4, tlv_length);
+			}
+			break;
+		case MCP_TYPE_TIMESTAMP:
+			if (tlv_length == 4) {
+				proto_tree_add_item(tlv_tree, hf_mcp_timestamp, tvb, offset, tlv_length, ENC_TIME_SECS|ENC_BIG_ENDIAN);
+				timestamp = tvb_get_ntohl(tvb, offset);
+				timestamp_str = abs_time_secs_to_str(wmem_packet_scope(), timestamp, ABSOLUTE_TIME_LOCAL, TRUE);
+				proto_item_append_text(tlv_tree, ": %s", timestamp_str);
+				col_append_fstr(pinfo->cinfo, COL_INFO, "time/%s ", timestamp_str);
+			} else {
+				proto_tree_add_expert_format(mcp_tree, pinfo, &ei_mcp_unexpected_tlv_length, tvb,
+					offset, tlv_length, "Expected value length differs from seen length (%u != %u)",
+					4, tlv_length);
+			}
+			break;
+		case MCP_TYPE_HMAC:
+			if (tlv_length == 20) {
+				proto_tree_add_item(tlv_tree, hf_mcp_hmac, tvb, offset, tlv_length, ENC_NA);
+			} else {
+				proto_tree_add_expert_format(mcp_tree, pinfo, &ei_mcp_unexpected_tlv_length, tvb,
+					offset, tlv_length, "Expected value length differs from seen length (%u != %u)",
+					20, tlv_length);
+			}
+			break;
+		case MCP_TYPE_END:
+			last = TRUE;
+			if (tlv_length != 0) {
+				proto_tree_add_expert_format(mcp_tree, pinfo, &ei_mcp_unexpected_tlv_length, tvb,
+					offset, tlv_length, "Expected value length differs from seen length (%u != %u)",
+					0, tlv_length);
+			}
+			break;
+		default:
+			proto_tree_add_item(tlv_tree, hf_mcp_unknown, tvb, offset, tlv_length, ENC_NA);
+			break;
+		}
+		offset += tlv_length;
+	}
+	if (offset < data_length) {
+		proto_tree_add_expert(mcp_tree, pinfo, &ei_mcp_trailing_bytes, tvb, offset,
+			data_length - offset);
+	}
+
+	return tvb_captured_length(tvb);
+}
+
+void
+proto_register_mcp(void)
+{
+	static hf_register_info hf[] = {
+
+	/* TLV header (aka TL) */
+		{ &hf_mcp_tlv_type,
+		{ "TLV type",	"mcp.tlv.type", FT_UINT8, BASE_DEC, VALS(mcp_type_vals),
+			0x0, NULL, HFILL }},
+
+		{ &hf_mcp_tlv_length,
+		{ "TLV length",	"mcp.tlv.length", FT_UINT16, BASE_DEC, NULL,
+			0x0, NULL, HFILL }},
+
+	/* TLV data (aka V) */
+		{ &hf_mcp_1,
+		{ "Type1",	"mcp.type1", FT_UINT32, BASE_DEC, NULL,
+			0x0, NULL, HFILL }},
+
+		{ &hf_mcp_switchid,
+		{ "Switch ID",	"mcp.switchid", FT_UINT32, BASE_DEC, NULL,
+			0x0, "Originating Switch", HFILL }},
+
+		{ &hf_mcp_3,
+		{ "Type3",	"mcp.type3", FT_BYTES, BASE_NONE, NULL,
+			0x0, NULL, HFILL }},
+
+		{ &hf_mcp_ifindex,
+		{ "IfIndex",	"mcp.ifindex", FT_UINT32, BASE_HEX, NULL,
+			0x0, NULL, HFILL }},
+
+		{ &hf_mcp_timestamp,
+		{ "Timestamp",	"mcp.timestamp", FT_ABSOLUTE_TIME, ABSOLUTE_TIME_LOCAL, NULL,
+			0x0, NULL, HFILL }},
+
+		{ &hf_mcp_hmac,
+		{ "HMAC(?)",	"mcp.hmac", FT_BYTES, BASE_NONE, NULL,
+			0x0, NULL, HFILL }},
+
+		{ &hf_mcp_unknown,
+		{ "Unknown",	"mcp.unknown", FT_BYTES, BASE_NONE, NULL,
+			0x0, NULL, HFILL }},
+
+	};
+
+	static gint *ett[] = {
+		&ett_mcp,
+		&ett_mcp_tlv_header,
+	};
+
+	static ei_register_info ei[] = {
+		{ &ei_mcp_short_tlv,
+		{ "mcp.short_tlv", PI_MALFORMED, PI_ERROR,
+			"TLV is too short", EXPFILL }},
+
+		{ &ei_mcp_trailing_bytes,
+		{ "mcp.trailing_bytes", PI_PROTOCOL, PI_WARN,
+			"Trailing bytes after last TLV", EXPFILL }},
+
+		{ &ei_mcp_unexpected_tlv_length,
+		{ "mcp.unexpected_tlv_length", PI_PROTOCOL, PI_WARN,
+			"Expected Value length differs from seen length", EXPFILL }},
+	};
+
+	expert_module_t* expert_mcp;
+
+	proto_mcp = proto_register_protocol(PROTO_LONG_NAME, PROTO_SHORT_NAME, "mcp");
+	proto_register_field_array(proto_mcp, hf, array_length(hf));
+	proto_register_subtree_array(ett, array_length(ett));
+	expert_mcp = expert_register_protocol(proto_mcp);
+	expert_register_field_array(expert_mcp, ei, array_length(ei));
+}
+
+void
+proto_reg_handoff_mcp(void)
+{
+	dissector_handle_t mcp_handle;
+
+	mcp_handle = create_dissector_handle(dissect_mcp, proto_mcp);
+	dissector_add_uint("llc.cisco_pid", CISCO_PID_MCP, mcp_handle);
+}
+
+/*
+ * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
+ *
+ * Local variables:
+ * c-basic-offset: 8
+ * tab-width: 8
+ * indent-tabs-mode: t
+ * End:
+ *
+ * vi: set shiftwidth=8 tabstop=8 noexpandtab:
+ * :indentSize=8:tabSize=8:noTabs=false:
+ */