/* packet-i2c.c * Routines for I2C captures (using libpcap extensions) * * Pigeon Point Systems * * Wireshark - Network traffic analyzer * By Gerald Combs * Copyright 1998 Gerald Combs * * SPDX-License-Identifier: GPL-2.0-or-later */ #include "config.h" #include #include #include #include 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 = ""; 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: */