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wireshark/epan/dissectors/packet-hcrt.c

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/* packet-hcrt.c
*
* Routines for Hotline Command-Response Transaction (HCrt)
* Protocol specifications (draft) are available here
* https://github.com/ShepardSiegel/hotline/tree/master/doc
*
* Copyright 2013 Dario Lombardo (lomato@gmail.com)
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "config.h"
#include <epan/packet.h>
#include <epan/prefs.h>
#include <epan/expert.h>
static int proto_hcrt = -1;
#define HCRT_UDP_PORTS_DEFAULT "47000"
static guint ethertype_pref = 0xf052;
static int hf_hcrt_header = -1;
static int hf_hcrt_message_tag = -1;
static int hf_hcrt_message_type = -1;
static int hf_hcrt_am = -1;
static int hf_hcrt_do = -1;
static int hf_hcrt_1st_dword_enable = -1;
static int hf_hcrt_last_dword_enable = -1;
static int hf_hcrt_resp_code = -1;
static int hf_hcrt_adl = -1;
static int hf_hcrt_last = -1;
static int hf_hcrt_body = -1;
static int hf_hcrt_addr_32 = -1;
static int hf_hcrt_addr_64 = -1;
static int hf_hcrt_data_32 = -1;
static int hf_hcrt_data_64 = -1;
static int hf_hcrt_command_nop = -1;
static gint ett_hcrt = -1;
static gint ett_hcrt_msg = -1;
static gint ett_hcrt_hdr = -1;
static gint ett_hcrt_body = -1;
static expert_field ei_hcrt_error = EI_INIT;
void proto_reg_handoff_hcrt(void);
void proto_register_hcrt(void);
#define HCRT_HDR_LEN 4
#define HCRT_NOP 0x0
#define HCRT_WRITE 0x1
#define HCRT_READ 0x2
#define HCRT_RESPONSE 0x3
#define ADDR_MODE_32 1
#define ADDR_MODE_64 2
/* Message types */
static const value_string hcrt_message_types[] = {
{0x00, "NOP"},
{0x01, "Write"},
{0x02, "Read"},
{0x03, "Response"},
{0, NULL}
};
/* Addressing modes */
static const value_string hcrt_ams[] = {
{0x0, "32 bit"},
{0x1, "64 bit"},
{0, NULL}
};
/* Discovery operations */
static const true_false_string hcrt_dos = {
"DO",
"not DO",
};
static const value_string dword_enable_vals[] = {
{0xF, "4B"},
{0xC, "2B (MS)"},
{0x3, "2B (LS)"},
{0x8, "1B (B3)"},
{0x4, "1B (B2)"},
{0x2, "1B (B1)"},
{0x1, "1B (B0)"},
{0, NULL}
};
static const value_string response_codes[] = {
{0x0, "OK"},
{0x1, "Timeout"},
{0x2, "Error"},
{0x3, "Reserved"},
{0x4, "Reserved"},
{0x5, "Reserved"},
{0x6, "Reserved"},
{0x7, "Reserved"},
{0x8, "Reserved"},
{0x9, "Reserved"},
{0xa, "Reserved"},
{0xb, "Reserved"},
{0xc, "Reserved"},
{0xd, "Reserved"},
{0xe, "Reserved"},
{0xf, "Reserved"},
{0, NULL}
};
static void dissect_hcrt_body(tvbuff_t* tvb, proto_tree* tree , guint* offset,
int type, int addr_mode, int adl, int body_len)
{
proto_item* ti_body;
proto_tree* hcrt_body_tree;
gint i;
ti_body = proto_tree_add_item(tree, hf_hcrt_body, tvb, *offset, body_len, ENC_NA);
hcrt_body_tree = proto_item_add_subtree(ti_body, ett_hcrt_body);
switch (type) {
case HCRT_NOP:
proto_tree_add_item(hcrt_body_tree, hf_hcrt_command_nop, tvb, *offset,
body_len, ENC_NA);
break;
case HCRT_WRITE:
if (addr_mode == ADDR_MODE_32) {
/* Address (32) */
proto_tree_add_item(hcrt_body_tree, hf_hcrt_addr_32, tvb, *offset,
4, ENC_LITTLE_ENDIAN);
/* Data */
for (i = 1; i <= adl; i++) {
proto_tree_add_item(hcrt_body_tree, hf_hcrt_data_32, tvb,
*offset + i * 4, 4, ENC_LITTLE_ENDIAN);
}
} else {
/* Address (64) */
proto_tree_add_item(hcrt_body_tree, hf_hcrt_addr_64, tvb, *offset,
8, ENC_LITTLE_ENDIAN);
/* Data */
for (i = 1; i <= adl; i++)
proto_tree_add_item(hcrt_body_tree, hf_hcrt_data_64, tvb,
*offset + i * 8, 8, ENC_LITTLE_ENDIAN);
}
break;
case HCRT_READ:
if (addr_mode == ADDR_MODE_32) {
/* Address (32) */
proto_tree_add_item(hcrt_body_tree, hf_hcrt_addr_32, tvb, *offset, 4,
ENC_LITTLE_ENDIAN);
} else {
/* Address (64) */
proto_tree_add_item(hcrt_body_tree, hf_hcrt_addr_64, tvb, *offset, 8,
ENC_LITTLE_ENDIAN);
}
break;
case HCRT_RESPONSE:
if (body_len > 0) {
proto_tree_add_item(hcrt_body_tree, hf_hcrt_command_nop, tvb, *offset,
body_len, ENC_NA);
}
break;
default:
DISSECTOR_ASSERT_NOT_REACHED();
break;
}
(*offset) += body_len;
}
/* Returns true if this is the last message */
static gboolean dissect_hcrt_header(tvbuff_t* tvb, packet_info* pinfo, proto_tree* tree,
guint* offset, guint8 b0_first, guint8 b0_current)
{
proto_item* ti_hdr;
proto_tree* hcrt_hdr_tree;
gboolean last;
guint8 type;
ti_hdr = proto_tree_add_item(tree, hf_hcrt_header, tvb, *offset, 4, ENC_NA);
hcrt_hdr_tree = proto_item_add_subtree(ti_hdr, ett_hcrt_hdr);
if (b0_first != b0_current) {
expert_add_info_format(pinfo, hcrt_hdr_tree, &ei_hcrt_error,
"Invalid Byte 0 in Header. Must be equal in all HCrt messages. "
"Expected: %.2X, got: %.2X", b0_first, b0_current);
}
type = (b0_current & 0x30) >> 4;
/* == Byte 0 == */
/* TAG */
proto_tree_add_item(hcrt_hdr_tree, hf_hcrt_message_tag, tvb,
*offset, 1, ENC_NA);
/* Message Type */
proto_tree_add_item(hcrt_hdr_tree, hf_hcrt_message_type, tvb,
*offset, 1, ENC_NA);
/* Addressing Mode */
proto_tree_add_item(hcrt_hdr_tree, hf_hcrt_am, tvb,
*offset, 1, ENC_NA);
/* Discovery Operation */
proto_tree_add_item(hcrt_hdr_tree, hf_hcrt_do, tvb,
*offset, 1, ENC_NA);
(*offset)++;
/* == Byte 1 == */
if (type != HCRT_RESPONSE) {
/* 1st DWORD enable */
proto_tree_add_item(hcrt_hdr_tree, hf_hcrt_1st_dword_enable, tvb,
*offset, 1, ENC_NA);
} else {
/* Response Code */
proto_tree_add_item(hcrt_hdr_tree, hf_hcrt_resp_code, tvb,
*offset, 1, ENC_NA);
}
if (type != HCRT_RESPONSE) {
/* Last DWORD enable */
proto_tree_add_item(hcrt_hdr_tree, hf_hcrt_last_dword_enable, tvb,
*offset, 1, ENC_NA);
}
(*offset)++;
/* == Byte 2 & 3 == */
/* ADL */
proto_tree_add_item(hcrt_hdr_tree, hf_hcrt_adl, tvb, *offset, 2, ENC_LITTLE_ENDIAN);
/* Last */
proto_tree_add_item(hcrt_hdr_tree, hf_hcrt_last, tvb, *offset, 2, ENC_LITTLE_ENDIAN);
/* last */
last = (tvb_get_letohs(tvb, *offset) & 0x8000) != 0;
(*offset) += 2;
return last;
}
/* Return true if this is the last message */
static gboolean dissect_hcrt_message(tvbuff_t* tvb, packet_info* pinfo, proto_tree* tree,
guint* offset, guint8 b0_first, int i)
{
gboolean last;
guint adl;
guint addr_mode;
guint body_len;
proto_tree* hcrt_msg_tree;
guint8 b0_current;
int type;
/* Save byte 0 of current packet */
b0_current = tvb_get_guint8(tvb, *offset);
/* Get details from header */
adl = tvb_get_letohs(tvb, *offset + 2) & 0x0FFF;
addr_mode = (1 + ((b0_current & 0x40) >> 6));
type = (b0_current & 0x30) >> 4;
switch (type) {
case HCRT_NOP:
body_len = 4 * addr_mode * adl;
break;
case HCRT_WRITE:
body_len = 4 * addr_mode * (adl + 1);
break;
case HCRT_READ:
body_len = 4 * addr_mode;
break;
case HCRT_RESPONSE:
body_len = 4 * addr_mode * adl;
break;
default:
DISSECTOR_ASSERT_NOT_REACHED();
break;
}
hcrt_msg_tree = proto_tree_add_subtree_format(tree, tvb, *offset,
HCRT_HDR_LEN + body_len, ett_hcrt_msg, NULL, "Message %d", i);
last = dissect_hcrt_header(tvb, pinfo, hcrt_msg_tree, offset, b0_first, b0_current);
dissect_hcrt_body(tvb, hcrt_msg_tree, offset, type, addr_mode, adl, body_len);
return last;
}
static int dissect_hcrt(tvbuff_t* tvb, packet_info* pinfo, proto_tree* tree, void* data _U_)
{
guint8 type;
proto_item* ti;
proto_tree* hcrt_tree;
guint offset;
int i = 1;
guint8 b0_first;
guint8 tag;
guint adl;
col_set_str(pinfo->cinfo, COL_PROTOCOL, "HCrt");
col_clear(pinfo->cinfo, COL_INFO);
/* Save byte 0 of first message. Will be checked against byte 0 of other messages */
b0_first = tvb_get_guint8(tvb, 0);
tag = b0_first & 0x0F;
type = (b0_first & 0x30) >> 4;
adl = tvb_get_letohs(tvb, 2) & 0x0FFF;
col_add_fstr(pinfo->cinfo, COL_INFO, "Type: %s, Tag: 0x%X, ADL: %u",
val_to_str(type, hcrt_message_types, "Unknown (0x%02x)"), tag, adl);
if (adl == 1) {
if (type == HCRT_READ || type == HCRT_WRITE) {
col_append_fstr(pinfo->cinfo, COL_INFO, ", Address: 0x%.8X", tvb_get_letohl(tvb, 4));
}
if (type == HCRT_WRITE) {
col_append_fstr(pinfo->cinfo, COL_INFO, ", Data: 0x%.8X", tvb_get_letohl(tvb, 8));
}
}
offset = 0;
ti = proto_tree_add_item(tree, proto_hcrt, tvb, 0, -1, ENC_NA);
hcrt_tree = proto_item_add_subtree(ti, ett_hcrt);
while (!dissect_hcrt_message(tvb, pinfo, hcrt_tree, &offset, b0_first, i)) {
i++;
}
return tvb_captured_length(tvb);
}
void proto_register_hcrt(void)
{
expert_module_t* expert_hcrt;
module_t* hcrt_module;
static hf_register_info hf[] = {
{ &hf_hcrt_header,
{ "Header", "hcrt.hdr",
FT_NONE, BASE_NONE,
NULL, 0x00,
NULL, HFILL }
},
{ &hf_hcrt_message_tag,
{ "Tag", "hcrt.tag",
FT_UINT8, BASE_HEX,
NULL, 0x0F,
NULL, HFILL }
},
{ &hf_hcrt_message_type,
{ "Type", "hcrt.type",
FT_UINT8, BASE_DEC,
VALS(hcrt_message_types), 0x30,
NULL, HFILL }
},
{ &hf_hcrt_am,
{ "Addressing Mode", "hcrt.am",
FT_UINT8, BASE_DEC,
VALS(hcrt_ams), 0x40,
NULL, HFILL }
},
{ &hf_hcrt_do,
{ "Discovery Operation", "hcrt.do",
FT_BOOLEAN, 8,
TFS(&hcrt_dos), 0x80,
NULL, HFILL }
},
{ &hf_hcrt_1st_dword_enable,
{ "1st DWORD enable", "hcrt.first_dword_enable",
FT_UINT8, BASE_HEX,
VALS(dword_enable_vals), 0xF0,
NULL, HFILL }
},
{ &hf_hcrt_last_dword_enable,
{ "Last DWORD enable", "hcrt.last_dword_enable",
FT_UINT8, BASE_HEX,
VALS(dword_enable_vals), 0x0F,
NULL, HFILL }
},
{ &hf_hcrt_resp_code,
{ "Response code", "hcrt.response_code",
FT_UINT8, BASE_HEX,
VALS(response_codes), 0xF0,
NULL, HFILL }
},
{ &hf_hcrt_adl,
{ "ADL", "hcrt.adl",
FT_UINT16, BASE_DEC,
NULL, 0x0FFF,
NULL, HFILL }
},
{ &hf_hcrt_last,
{ "Last message", "hcrt.last",
FT_BOOLEAN, 16,
NULL, 0x8000,
NULL, HFILL }
},
{ &hf_hcrt_body,
{ "Body", "hcrt.body",
FT_NONE, BASE_NONE,
NULL, 0x00,
NULL, HFILL }
},
{ &hf_hcrt_addr_32,
{ "Address", "hcrt.address32",
FT_UINT32, BASE_HEX,
NULL, 0x0,
NULL, HFILL }
},
{ &hf_hcrt_addr_64,
{ "Address", "hcrt.address64",
FT_UINT64, BASE_HEX,
NULL, 0x0,
NULL, HFILL }
},
{ &hf_hcrt_data_32,
{ "Data", "hcrt.data32",
FT_UINT32, BASE_HEX,
NULL, 0x0,
NULL, HFILL }
},
{ &hf_hcrt_data_64,
{ "Data", "hcrt.data64",
FT_UINT64, BASE_HEX,
NULL, 0x0,
NULL, HFILL }
},
{ &hf_hcrt_command_nop,
{ "Command", "hcrt.command_nop",
FT_BYTES, BASE_NONE,
NULL, 0x0,
NULL, HFILL }
}
};
static ei_register_info ei[] = {
{ &ei_hcrt_error, { "hcrt.error", PI_MALFORMED, PI_ERROR, "Unusual error code", EXPFILL }}
};
/* Setup protocol subtree array */
static gint* ett[] = {
&ett_hcrt,
&ett_hcrt_msg,
&ett_hcrt_hdr,
&ett_hcrt_body,
};
proto_hcrt = proto_register_protocol ("Hotline Command-Response Transaction protocol", "HCrt", "hcrt");
proto_register_field_array(proto_hcrt, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
expert_hcrt = expert_register_protocol(proto_hcrt);
expert_register_field_array(expert_hcrt, ei, array_length(ei));
hcrt_module = prefs_register_protocol(proto_hcrt, proto_reg_handoff_hcrt);
prefs_register_uint_preference(hcrt_module,
"dissector_ethertype",
"Ethernet type",
"The ethernet type used for L2 communications",
10, &ethertype_pref);
}
void proto_reg_handoff_hcrt(void)
{
static dissector_handle_t hcrt_handle;
static gboolean hcrt_prefs_initialized = FALSE;
static gint hcrt_ethertype;
if (!hcrt_prefs_initialized) {
hcrt_handle = create_dissector_handle(dissect_hcrt, proto_hcrt);
/* Also register as a dissector that can be selected by a TCP port number via
"decode as" */
dissector_add_for_decode_as_with_preference("tcp.port", hcrt_handle);
dissector_add_uint_range_with_preference("udp.port", HCRT_UDP_PORTS_DEFAULT, hcrt_handle);
hcrt_prefs_initialized = TRUE;
} else {
dissector_delete_uint("ethertype", hcrt_ethertype, hcrt_handle);
}
hcrt_ethertype = ethertype_pref;
dissector_add_uint("ethertype", hcrt_ethertype, hcrt_handle);
}
/*
* Editor modelines - https://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 4
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* vi: set shiftwidth=4 tabstop=8 expandtab:
* :indentSize=4:tabSize=8:noTabs=true:
*/
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