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/* packet-i2c.c
* Routines for I2C captures (using libpcap extensions)
*
* Pigeon Point Systems <www.pigeonpoint.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/capture_dissectors.h>
#include <epan/prefs.h>
#include <epan/decode_as.h>
void proto_register_i2c(void);
void proto_reg_handoff_i2c(void);
static dissector_handle_t i2c_linux_handle;
static capture_dissector_handle_t i2c_linux_cap_handle;
static dissector_handle_t i2c_kontron_handle;
static int proto_i2c;
static int proto_i2c_event;
static int proto_i2c_data;
static int hf_i2c_bus;
static int hf_i2c_event;
static int hf_i2c_flags;
static int hf_i2c_addr;
static int ett_i2c;
static dissector_table_t subdissector_table;
static dissector_handle_t ipmb_handle;
/* I2C packet flags. */
#define I2C_FLAG_RD 0x00000001
#define I2C_FLAG_TEN 0x00000010
#define I2C_FLAG_REV_DIR_ADDR 0x00002000
#define I2C_FLAG_NOSTART 0x00004000
/* I2C events. */
#define I2C_EVENT_PROM_ON (1 << 0) /* Promiscuous mode: on */
#define I2C_EVENT_PROM_OFF (1 << 1) /* Promiscuous mode: off */
#define I2C_EVENT_ONLINE_ON (1 << 2) /* Online state: on */
#define I2C_EVENT_ONLINE_OFF (1 << 3) /* Online state: off */
#define I2C_EVENT_ATTACHED_ON (1 << 4) /* Attached state: on */
#define I2C_EVENT_ATTACHED_OFF (1 << 5) /* Attached state: off */
#define I2C_EVENT_PROM_OVFL_ON (1 << 6) /* Prom. queue overflow: on */
#define I2C_EVENT_PROM_OVFL_OFF (1 << 7) /* Prom. queue overflow: off */
#define I2C_EVENT_OVFL_ON (1 << 8) /* Queue overflow: on */
#define I2C_EVENT_OVFL_OFF (1 << 9) /* Queue overflow: off */
/* I2C errors. */
#define I2C_EVENT_ERR_DATA_LO (1 << 16) /* Unable to drive data LO */
#define I2C_EVENT_ERR_DATA_HI (1 << 17) /* Unable to drive data HI */
#define I2C_EVENT_ERR_CLOCK_LO (1 << 18) /* Unable to drive clock LO */
#define I2C_EVENT_ERR_CLOCK_HI (1 << 19) /* Unable to drive clock HI */
#define I2C_EVENT_ERR_CLOCK_TO (1 << 20) /* Clock low timeout */
#define I2C_EVENT_ERR_PHYS (1 << 21) /* The I2C bus controller
has been physically
disconnected from the bus */
#define I2C_EVENT_ERR_FAIL (1 << 22) /* Undiagnosed failure */
static void i2c_prompt(packet_info *pinfo _U_, char* result)
{
snprintf(result, MAX_DECODE_AS_PROMPT_LEN, "Interpret I2C messages as");
}
static bool
capture_i2c_linux(const unsigned char *pd _U_, int offset _U_, int len _U_, capture_packet_info_t *cpinfo, const union wtap_pseudo_header *pseudo_header)
{
if (pseudo_header->i2c.is_event) {
capture_dissector_increment_count(cpinfo, proto_i2c_event);
} else {
capture_dissector_increment_count(cpinfo, proto_i2c_data);
}
return true;
}
static const char *
i2c_linux_get_event_desc(uint32_t event)
{
const char *desc;
switch (event & 0x0000ffff) {
case I2C_EVENT_PROM_ON:
desc = "Promiscuous mode is enabled";
break;
case I2C_EVENT_PROM_OFF:
desc = "Promiscuous mode is disabled";
break;
case I2C_EVENT_ONLINE_ON:
desc = "The I2C controller is operational";
break;
case I2C_EVENT_ONLINE_OFF:
desc = "The I2C controller is non-operational";
break;
case I2C_EVENT_ATTACHED_ON:
desc = "The I2C controller is attached to an I2C bus";
break;
case I2C_EVENT_ATTACHED_OFF:
desc = "The I2C controller is detached from an I2C bus";
if (event & I2C_EVENT_ERR_DATA_LO) {
desc = "The I2C controller is detached from an I2C bus: "
"unable to drive data LO";
} else if (event & I2C_EVENT_ERR_DATA_HI) {
desc = "The I2C controller is detached from an I2C bus: "
"unable to drive data HI";
} else if (event & I2C_EVENT_ERR_CLOCK_LO) {
desc = "The I2C controller is detached from an I2C bus: "
"unable to drive clock LO";
} else if (event & I2C_EVENT_ERR_CLOCK_HI) {
desc = "The I2C controller is detached from an I2C bus: "
"unable to drive clock HI";
} else if (event & I2C_EVENT_ERR_CLOCK_TO) {
desc = "The I2C controller is detached from an I2C bus: "
"clock low timeout";
} else if (event & I2C_EVENT_ERR_PHYS) {
desc = "The I2C controller is detached from an I2C bus: "
"the I2C bus controller has been physically "
"disconnected from the bus";
} else if (event & I2C_EVENT_ERR_FAIL) {
desc = "The I2C controller is detached from an I2C bus: "
"undiagnosed failure";
}
break;
case I2C_EVENT_PROM_OVFL_ON:
desc = "The incoming promiscuous data buffer has been overrun; "
"some data is lost";
break;
case I2C_EVENT_PROM_OVFL_OFF:
desc = "The incoming promiscuous data buffer is available";
break;
case I2C_EVENT_OVFL_ON:
desc = "The incoming I2C data buffer has been overrun; "
"some data is lost";
break;
case I2C_EVENT_OVFL_OFF:
desc = "The incoming I2C data buffer is available";
break;
default:
desc = "<unknown state event>";
break;
}
return desc;
}
static int
dissect_i2c_linux(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
proto_item *ti;
proto_tree *i2c_tree;
uint8_t is_event;
uint8_t bus, addr;
uint32_t flags;
flags = pinfo->pseudo_header->i2c.flags;
bus = pinfo->pseudo_header->i2c.bus;
col_add_fstr(pinfo->cinfo, COL_DEF_SRC, "I2C-%d", bus);
is_event = pinfo->pseudo_header->i2c.is_event;
if (is_event) {
addr = 0;
col_set_str(pinfo->cinfo, COL_PROTOCOL, "I2C Event");
col_set_str(pinfo->cinfo, COL_DEF_DST, "----");
col_add_str(pinfo->cinfo, COL_INFO,
i2c_linux_get_event_desc(flags));
} else {
/* Report 7-bit hardware address */
addr = tvb_get_uint8(tvb, 0) >> 1;
col_add_fstr(pinfo->cinfo, COL_PROTOCOL, "I2C %s",
(flags & I2C_FLAG_RD) ? "Read" : "Write");
col_add_fstr(pinfo->cinfo, COL_DEF_DST, "0x%02x", addr);
col_add_fstr(pinfo->cinfo, COL_INFO, "I2C %s, %d bytes",
(flags & I2C_FLAG_RD) ? "Read" : "Write", tvb_captured_length(tvb));
}
pinfo->ptype = PT_I2C;
ti = proto_tree_add_protocol_format(tree, proto_i2c, tvb, 0, -1,
"Inter-Integrated Circuit (%s)",
is_event ? "Event" : "Data");
i2c_tree = proto_item_add_subtree(ti, ett_i2c);
proto_tree_add_uint_format(i2c_tree, hf_i2c_bus, tvb, 0, 0, bus,
"Bus: I2C-%d", bus);
if (is_event) {
proto_tree_add_uint_format_value(i2c_tree, hf_i2c_event, tvb, 0, 0,
flags, "%s (0x%08x)",
i2c_linux_get_event_desc(flags), flags);
} else {
proto_tree_add_uint_format_value(i2c_tree, hf_i2c_addr, tvb, 0, 1,
addr, "0x%02x%s", addr, addr ? "" : " (General Call)");
proto_tree_add_uint(i2c_tree, hf_i2c_flags, tvb, 0, 0, flags);
if (!dissector_try_payload(subdissector_table, tvb, pinfo, tree))
{
call_data_dissector(tvb, pinfo, tree);
}
}
return tvb_captured_length(tvb);
}
/* IPMB-over-I2C, with Kontron pseudo-header */
static int
dissect_i2c_kontron(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
proto_item *ti;
proto_tree *i2c_tree;
int offset = 0;
uint8_t addr;
tvbuff_t *new_tvb;
col_set_str(pinfo->cinfo, COL_DEF_SRC, "I2C");
col_set_str(pinfo->cinfo, COL_PROTOCOL, "I2C");
ti = proto_tree_add_protocol_format(tree, proto_i2c, tvb, 0, -1,
"Inter-Integrated Circuit (Data)");
/* Data length field */
offset++;
/* Port number on which the message was received */
offset++;
/* Report 7-bit hardware address */
addr = tvb_get_uint8(tvb, offset) >> 1;
col_append_fstr(pinfo->cinfo, COL_PROTOCOL, " %s",
tvb_get_uint8(tvb, 0) & 0x01 ? "Read" : "Write");
col_add_fstr(pinfo->cinfo, COL_DEF_DST, "0x%02x", addr);
col_add_fstr(pinfo->cinfo, COL_INFO, "I2C, %d bytes",
tvb_captured_length(tvb));
pinfo->ptype = PT_I2C;
i2c_tree = proto_item_add_subtree(ti, ett_i2c);
proto_tree_add_uint_format_value(i2c_tree, hf_i2c_addr, tvb, 0, 3,
addr, "0x%02x%s", addr, addr ? "" : " (General Call)");
new_tvb = tvb_new_subset_remaining(tvb, offset);
call_dissector(ipmb_handle, new_tvb, pinfo, tree);
return tvb_captured_length(tvb);
}
void
proto_register_i2c(void)
{
static hf_register_info hf[] = {
{ &hf_i2c_bus, { "Bus ID", "i2c.bus", FT_UINT8, BASE_DEC, NULL, 0, NULL, HFILL }},
{ &hf_i2c_addr, { "Target address", "i2c.addr", FT_UINT8, BASE_HEX, NULL, 0, NULL, HFILL }},
{ &hf_i2c_event, { "Event", "i2c.event", FT_UINT32, BASE_HEX, NULL, 0, NULL, HFILL }},
{ &hf_i2c_flags, { "Flags", "i2c.flags", FT_UINT32, BASE_HEX, NULL, 0, NULL, HFILL }},
};
static int *ett[] = {
&ett_i2c
};
module_t *m;
proto_i2c = proto_register_protocol("Inter-Integrated Circuit", "I2C", "i2c");
proto_register_field_array(proto_i2c, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
/* Placeholders for capture statistics */
proto_i2c_event = proto_register_protocol_in_name_only("I2C Events", "I2C Events", "i2c_event", proto_i2c, FT_PROTOCOL);
proto_i2c_data = proto_register_protocol_in_name_only("I2C Data", "I2C Data", "i2c_data", proto_i2c, FT_PROTOCOL);
m = prefs_register_protocol_obsolete(proto_i2c);
prefs_register_obsolete_preference(m, "type");
subdissector_table = register_decode_as_next_proto(proto_i2c, "i2c.message", "I2C messages dissector", i2c_prompt);
i2c_linux_handle = register_dissector("i2c_linux", dissect_i2c_linux, proto_i2c);
i2c_linux_cap_handle = register_capture_dissector("i2c_linux", capture_i2c_linux, proto_i2c);
i2c_kontron_handle = register_dissector("i2c_kontron", dissect_i2c_kontron, proto_i2c);
}
void
proto_reg_handoff_i2c(void)
{
dissector_add_uint("wtap_encap", WTAP_ENCAP_I2C_LINUX, i2c_linux_handle);
capture_dissector_add_uint("wtap_encap", WTAP_ENCAP_I2C_LINUX, i2c_linux_cap_handle);
dissector_add_uint("wtap_encap", WTAP_ENCAP_IPMB_KONTRON, i2c_kontron_handle);
ipmb_handle = find_dissector("ipmb");
}
/*
* 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:
*/
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