/*
 * Copyright (C) 2011-2015 Andreas Steffen
 * HSR Hochschule fuer Technik Rapperswil
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * for more details.
 */

#include "imc_os_state.h"

#include <imc/imc_agent.h>
#include <imc/imc_msg.h>
#include <imc/imc_os_info.h>
#include <generic/generic_attr_bool.h>
#include <generic/generic_attr_string.h>
#include <ietf/ietf_attr.h>
#include <ietf/ietf_attr_attr_request.h>
#include "ietf/ietf_attr_fwd_enabled.h"
#include <ietf/ietf_attr_installed_packages.h>
#include <ietf/ietf_attr_numeric_version.h>
#include <ietf/ietf_attr_op_status.h>
#include <ietf/ietf_attr_product_info.h>
#include <ietf/ietf_attr_string_version.h>
#include <ita/ita_attr.h>
#include <ita/ita_attr_get_settings.h>
#include <ita/ita_attr_settings.h>

#include <tncif_pa_subtypes.h>

#include <pen/pen.h>
#include <utils/debug.h>

/* IMC definitions */

static const char imc_name[] = "OS";

static pen_type_t msg_types[] = {
	{ PEN_IETF, PA_SUBTYPE_IETF_OPERATING_SYSTEM }
};

static imc_agent_t *imc_os;
static imc_os_info_t *os;

/**
 * see section 3.8.1 of TCG TNC IF-IMC Specification 1.3
 */
TNC_Result TNC_IMC_API TNC_IMC_Initialize(TNC_IMCID imc_id,
										  TNC_Version min_version,
										  TNC_Version max_version,
										  TNC_Version *actual_version)
{
	if (imc_os)
	{
		DBG1(DBG_IMC, "IMC \"%s\" has already been initialized", imc_name);
		return TNC_RESULT_ALREADY_INITIALIZED;
	}
	imc_os = imc_agent_create(imc_name, msg_types, countof(msg_types),
							  imc_id, actual_version);
	if (!imc_os)
	{
		return TNC_RESULT_FATAL;
	}

	os = imc_os_info_create();
	if (!os)
	{
		imc_os->destroy(imc_os);
		imc_os = NULL;

		return TNC_RESULT_FATAL;
	}

	if (min_version > TNC_IFIMC_VERSION_1 || max_version < TNC_IFIMC_VERSION_1)
	{
		DBG1(DBG_IMC, "no common IF-IMC version");
		return TNC_RESULT_NO_COMMON_VERSION;
	}
	return TNC_RESULT_SUCCESS;
}

/**
 * see section 3.8.2 of TCG TNC IF-IMC Specification 1.3
 */
TNC_Result TNC_IMC_API TNC_IMC_NotifyConnectionChange(TNC_IMCID imc_id,
				TNC_ConnectionID connection_id, TNC_ConnectionState new_state)
{
	imc_state_t *state;

	if (!imc_os)
	{
		DBG1(DBG_IMC, "IMC \"%s\" has not been initialized", imc_name);
		return TNC_RESULT_NOT_INITIALIZED;
	}
	switch (new_state)
	{
		case TNC_CONNECTION_STATE_CREATE:
			state = imc_os_state_create(connection_id);
			return imc_os->create_state(imc_os, state);
		case TNC_CONNECTION_STATE_HANDSHAKE:
			if (imc_os->change_state(imc_os, connection_id, new_state,
				&state) != TNC_RESULT_SUCCESS)
			{
				return TNC_RESULT_FATAL;
			}
			state->set_result(state, imc_id,
							  TNC_IMV_EVALUATION_RESULT_DONT_KNOW);
			return TNC_RESULT_SUCCESS;
		case TNC_CONNECTION_STATE_DELETE:
			return imc_os->delete_state(imc_os, connection_id);
		default:
			return imc_os->change_state(imc_os, connection_id,
											 new_state, NULL);
	}
}

/**
 * Add IETF Product Information attribute to the send queue
 */
static void add_product_info(imc_msg_t *msg)
{
	pa_tnc_attr_t *attr;
	os_type_t os_type;
	pen_t vendor_id = PEN_IETF;
	int i;

	typedef struct vendor_pen_t {
		os_type_t os_type;
		pen_t pen;
	} vendor_pen_t;

	vendor_pen_t vendor_pens[] = {
		{ OS_TYPE_DEBIAN,  PEN_DEBIAN },
		{ OS_TYPE_UBUNTU,  PEN_CANONICAL },
		{ OS_TYPE_FEDORA,  PEN_FEDORA },
		{ OS_TYPE_REDHAT,  PEN_REDHAT },
		{ OS_TYPE_ANDROID, PEN_GOOGLE }
	};

	os_type = os->get_type(os);
	for (i = 0; i < countof(vendor_pens); i++)
	{
		if (os_type == vendor_pens[i].os_type)
		{
			vendor_id = vendor_pens[i].pen;
			break;
		}
	}
	attr = ietf_attr_product_info_create(vendor_id, 0, os->get_name(os));
	msg->add_attribute(msg, attr);
}

/**
 * Add IETF Numeric Version attribute to the send queue
 */
static void add_numeric_version(imc_msg_t *msg)
{
	pa_tnc_attr_t *attr;
	uint32_t major, minor;

	os->get_numeric_version(os, &major, &minor);
	DBG1(DBG_IMC, "operating system numeric version is %d.%d",
				   major, minor);

	attr = ietf_attr_numeric_version_create(major, minor, 0, 0, 0);
	msg->add_attribute(msg, attr);
}

/**
 * Add IETF String Version attribute to the send queue
 */
static void add_string_version(imc_msg_t *msg)
{
	pa_tnc_attr_t *attr;

	attr = ietf_attr_string_version_create(os->get_version(os),
										   chunk_empty, chunk_empty);
	msg->add_attribute(msg, attr);
}

/**
 * Add IETF Operational Status attribute to the send queue
 */
static void add_op_status(imc_msg_t *msg)
{
	pa_tnc_attr_t *attr;
	time_t uptime, last_boot;

	uptime = os->get_uptime(os);
	last_boot = uptime ? time(NULL) - uptime : UNDEFINED_TIME;
	if (last_boot != UNDEFINED_TIME)
	{
		DBG1(DBG_IMC, "last boot: %T, %u s ago", &last_boot, TRUE, uptime);
	}
	attr = ietf_attr_op_status_create(OP_STATUS_OPERATIONAL,
									  OP_RESULT_SUCCESSFUL, last_boot);
	msg->add_attribute(msg, attr);
}

/**
 * Add IETF Forwarding Enabled attribute to the send queue
 */
static void add_fwd_enabled(imc_msg_t *msg)
{
	pa_tnc_attr_t *attr;
	os_fwd_status_t fwd_status;

	fwd_status = os->get_fwd_status(os);
	DBG1(DBG_IMC, "IPv4 forwarding is %N", os_fwd_status_names, fwd_status);
	attr = ietf_attr_fwd_enabled_create(fwd_status,
				pen_type_create(PEN_IETF, IETF_ATTR_FORWARDING_ENABLED));
	msg->add_attribute(msg, attr);
}

/**
 * Add IETF Factory Default Password Enabled attribute to the send queue
 */
static void add_default_pwd_enabled(imc_msg_t *msg)
{
	pa_tnc_attr_t *attr;
	bool status;

	status = os->get_default_pwd_status(os);
	DBG1(DBG_IMC, "factory default password is %sabled", status ? "en" : "dis");
	attr = generic_attr_bool_create(status,
			pen_type_create(PEN_IETF, IETF_ATTR_FACTORY_DEFAULT_PWD_ENABLED));
	msg->add_attribute(msg, attr);
}

/**
 * Add ITA Device ID attribute to the send queue
 */
static void add_device_id(imc_msg_t *msg)
{
	pa_tnc_attr_t *attr;
	chunk_t chunk, value = chunk_empty, keyid;
	char *name, *device_id, *device_handle, *cert_path;
	certificate_t *cert = NULL;
	private_key_t *privkey = NULL;
	public_key_t *pubkey;

	/* Get the device ID as a character string */
	device_id = lib->settings->get_str(lib->settings,
						"%s.plugins.imc-os.device_id", NULL, lib->ns);
	if (device_id)
	{
		value = chunk_clone(chunk_from_str(device_id));
	}

	if (value.len == 0)
	{
		/* Derive the device ID from a private key bound to a smartcard or TPM */
		device_handle = lib->settings->get_str(lib->settings,
						"%s.plugins.imc-os.device_handle", NULL, lib->ns);
		if (device_handle)
		{
			chunk = chunk_from_hex(
					chunk_create(device_handle, strlen(device_handle)), NULL);
			privkey = lib->creds->create(lib->creds, CRED_PRIVATE_KEY, KEY_ANY,
										 BUILD_PKCS11_KEYID, chunk, BUILD_END);
			free(chunk.ptr);

			if (privkey)
			{
				if (privkey->get_fingerprint(privkey, KEYID_PUBKEY_INFO_SHA1,
											 &keyid))
				{
					value = chunk_to_hex(keyid, NULL, FALSE);
				}
				privkey->destroy(privkey);

			}
		}
	}

	if (value.len == 0)
	{
		/* Derive the device ID from a raw public key */
		cert_path = lib->settings->get_str(lib->settings,
							"%s.plugins.imc-os.device_pubkey", NULL, lib->ns);
		if (cert_path)
		{
			cert = lib->creds->create(lib->creds, CRED_CERTIFICATE,
									  CERT_TRUSTED_PUBKEY, BUILD_FROM_FILE,
									  cert_path, BUILD_END);
			if (cert)
			{
				DBG2(DBG_IMC, "loaded device public key from '%s'", cert_path);
			}
			else
			{
				DBG1(DBG_IMC, "loading device public key from '%s' failed",
							   cert_path);
			}
		}

		if (!cert)
		{
			/* Derive the device ID from the public key contained in a certificate */
			cert_path = lib->settings->get_str(lib->settings,
								"%s.plugins.imc-os.device_cert", NULL, lib->ns);
			if (cert_path)
			{
				cert = lib->creds->create(lib->creds, CRED_CERTIFICATE,
										  CERT_X509, BUILD_FROM_FILE,
										  cert_path, BUILD_END);
				if (cert)
				{
					DBG2(DBG_IMC, "loaded device certificate from '%s'", cert_path);
				}
				else
				{
					DBG1(DBG_IMC, "loading device certificate from '%s' failed",
								   cert_path);
				}
			}
		}

		/* Compute the SHA-1 keyid of the retrieved device public key */
		if (cert)
		{
			pubkey = cert->get_public_key(cert);
			if (pubkey)
			{
				if (pubkey->get_fingerprint(pubkey, KEYID_PUBKEY_INFO_SHA1,
											&keyid))
				{
					value = chunk_to_hex(keyid, NULL, FALSE);
				}
				pubkey->destroy(pubkey);
			}
			cert->destroy(cert);
		}
	}

	if (value.len == 0)
	{
		/* Derive the device ID from some unique OS settings */
		name = os->get_type(os) == OS_TYPE_ANDROID ?
					  "android_id" : "/var/lib/dbus/machine-id";
		value = os->get_setting(os, name);

		/* Trim trailing newline character */
		if (value.len > 0 && value.ptr[value.len - 1] == '\n')
		{
			value.len--;
		}
	}

	if (value.len == 0)
	{
		DBG1(DBG_IMC, "no device ID available");
		return;
	}

	DBG1(DBG_IMC, "device ID is %.*s", value.len, value.ptr);
	attr = generic_attr_string_create(value, pen_type_create(PEN_ITA,
									  ITA_ATTR_DEVICE_ID));
	msg->add_attribute(msg, attr);
	free(value.ptr);
}

/**
 * Add an IETF Installed Packages attribute to the send queue
 */
static void add_installed_packages(imc_state_t *state, imc_msg_t *msg)
{
	pa_tnc_attr_t *attr;
	ietf_attr_installed_packages_t *attr_cast;
	enumerator_t *enumerator;
	chunk_t name, version;

	enumerator = os->create_package_enumerator(os);
	if (!enumerator)
	{
		return;
	}
	attr = ietf_attr_installed_packages_create();

	while (enumerator->enumerate(enumerator, &name, &version))
	{
		DBG2(DBG_IMC, "package '%.*s' (%.*s)",
					   name.len, name.ptr, version.len, version.ptr);
		attr_cast = (ietf_attr_installed_packages_t*)attr;
		attr_cast->add(attr_cast, name, version);
	}
	enumerator->destroy(enumerator);

	msg->add_attribute(msg, attr);
}

/**
 * Add ITA Settings attribute to the send queue
 */
static void add_settings(enumerator_t *enumerator, imc_msg_t *msg)
{
	pa_tnc_attr_t *attr = NULL;
	ita_attr_settings_t *attr_cast;
	chunk_t value;
	char *name;
	bool first = TRUE;

	while (enumerator->enumerate(enumerator, &name))
	{
		DBG1(DBG_IMC, "setting '%s'", name);

		value = os->get_setting(os, name);
		if (!value.ptr)
		{
			continue;
		}
		if (first)
		{
			attr = ita_attr_settings_create();
			first = FALSE;
		}
		attr_cast = (ita_attr_settings_t*)attr;
		attr_cast->add(attr_cast, name, value);
		chunk_free(&value);
	}

	if (attr)
	{
		msg->add_attribute(msg, attr);
	}
}

/**
 * see section 3.8.3 of TCG TNC IF-IMC Specification 1.3
 */
TNC_Result TNC_IMC_API TNC_IMC_BeginHandshake(TNC_IMCID imc_id,
											  TNC_ConnectionID connection_id)
{
	imc_state_t *state;
	imc_msg_t *out_msg;
	TNC_Result result = TNC_RESULT_SUCCESS;

	if (!imc_os)
	{
		DBG1(DBG_IMC, "IMC \"%s\" has not been initialized", imc_name);
		return TNC_RESULT_NOT_INITIALIZED;
	}
	if (!imc_os->get_state(imc_os, connection_id, &state))
	{
		return TNC_RESULT_FATAL;
	}
	if (lib->settings->get_bool(lib->settings,
								"%s.plugins.imc-os.push_info", TRUE, lib->ns))
	{
		out_msg = imc_msg_create(imc_os, state, connection_id, imc_id,
								 TNC_IMVID_ANY, msg_types[0]);
		add_product_info(out_msg);
		add_string_version(out_msg);
		add_numeric_version(out_msg);
		add_op_status(out_msg);
		add_fwd_enabled(out_msg);
		add_default_pwd_enabled(out_msg);
		add_device_id(out_msg);

		/* send PA-TNC message with the excl flag not set */
		result = out_msg->send(out_msg, FALSE);
		out_msg->destroy(out_msg);
	}

	return result;
}

static TNC_Result receive_message(imc_state_t *state, imc_msg_t *in_msg)
{
	imc_msg_t *out_msg;
	enumerator_t *enumerator;
	pa_tnc_attr_t *attr;
	pen_type_t type;
	TNC_Result result;
	bool fatal_error = FALSE;

	/* generate an outgoing PA-TNC message - we might need it */
	out_msg = imc_msg_create_as_reply(in_msg);

	/* parse received PA-TNC message and handle local and remote errors */
	result = in_msg->receive(in_msg, out_msg, &fatal_error);
	if (result != TNC_RESULT_SUCCESS)
	{
		out_msg->destroy(out_msg);
		return result;
	}

	/* analyze PA-TNC attributes */
	enumerator = in_msg->create_attribute_enumerator(in_msg);
	while (enumerator->enumerate(enumerator, &attr))
	{
		type = attr->get_type(attr);

		if (type.vendor_id == PEN_IETF)
		{
			if (type.type == IETF_ATTR_ATTRIBUTE_REQUEST)
			{
				ietf_attr_attr_request_t *attr_cast;
				pen_type_t *entry;
				enumerator_t *e;

				attr_cast = (ietf_attr_attr_request_t*)attr;

				e = attr_cast->create_enumerator(attr_cast);
				while (e->enumerate(e, &entry))
				{
					if (entry->vendor_id == PEN_IETF)
					{
						switch (entry->type)
						{
							case IETF_ATTR_PRODUCT_INFORMATION:
								add_product_info(out_msg);
								break;
							case IETF_ATTR_STRING_VERSION:
								add_string_version(out_msg);
								break;
							case IETF_ATTR_NUMERIC_VERSION:
								add_numeric_version(out_msg);
								break;
							case IETF_ATTR_OPERATIONAL_STATUS:
								add_op_status(out_msg);
								break;
							case IETF_ATTR_FORWARDING_ENABLED:
								add_fwd_enabled(out_msg);
								break;
							case IETF_ATTR_FACTORY_DEFAULT_PWD_ENABLED:
								add_default_pwd_enabled(out_msg);
								break;
							case IETF_ATTR_INSTALLED_PACKAGES:
								add_installed_packages(state, out_msg);
								break;
							default:
								break;
						}
					}
					else if (entry->vendor_id == PEN_ITA)
					{
						switch (entry->type)
						{
							case ITA_ATTR_DEVICE_ID:
								add_device_id(out_msg);
								break;
							default:
								break;
						}
					}
				}
				e->destroy(e);
			}
		}
		else if (type.vendor_id == PEN_ITA && type.type == ITA_ATTR_GET_SETTINGS)
		{
			ita_attr_get_settings_t *attr_cast;
			enumerator_t *e;

			attr_cast = (ita_attr_get_settings_t*)attr;

			e = attr_cast->create_enumerator(attr_cast);
			add_settings(e, out_msg);
			e->destroy(e);
		}
	}
	enumerator->destroy(enumerator);

	if (fatal_error)
	{
		result = TNC_RESULT_FATAL;
	}
	else
	{
		/* send PA-TNC message with the EXCL flag set */
		result = out_msg->send(out_msg, TRUE);
	}
	out_msg->destroy(out_msg);

	return result;
}

/**
 * see section 3.8.4 of TCG TNC IF-IMC Specification 1.3

 */
TNC_Result TNC_IMC_API TNC_IMC_ReceiveMessage(TNC_IMCID imc_id,
											  TNC_ConnectionID connection_id,
											  TNC_BufferReference msg,
											  TNC_UInt32 msg_len,
											  TNC_MessageType msg_type)
{
	imc_state_t *state;
	imc_msg_t *in_msg;
	TNC_Result result;

	if (!imc_os)
	{
		DBG1(DBG_IMC, "IMC \"%s\" has not been initialized", imc_name);
		return TNC_RESULT_NOT_INITIALIZED;
	}
	if (!imc_os->get_state(imc_os, connection_id, &state))
	{
		return TNC_RESULT_FATAL;
	}
	in_msg = imc_msg_create_from_data(imc_os, state, connection_id, msg_type,
									  chunk_create(msg, msg_len));
	result = receive_message(state, in_msg);
	in_msg->destroy(in_msg);

	return result;
}

/**
 * see section 3.8.6 of TCG TNC IF-IMV Specification 1.3
 */
TNC_Result TNC_IMC_API TNC_IMC_ReceiveMessageLong(TNC_IMCID imc_id,
												  TNC_ConnectionID connection_id,
												  TNC_UInt32 msg_flags,
												  TNC_BufferReference msg,
												  TNC_UInt32 msg_len,
												  TNC_VendorID msg_vid,
												  TNC_MessageSubtype msg_subtype,
												  TNC_UInt32 src_imv_id,
												  TNC_UInt32 dst_imc_id)
{
	imc_state_t *state;
	imc_msg_t *in_msg;
	TNC_Result result;

	if (!imc_os)
	{
		DBG1(DBG_IMC, "IMC \"%s\" has not been initialized", imc_name);
		return TNC_RESULT_NOT_INITIALIZED;
	}
	if (!imc_os->get_state(imc_os, connection_id, &state))
	{
		return TNC_RESULT_FATAL;
	}
	in_msg = imc_msg_create_from_long_data(imc_os, state, connection_id,
								src_imv_id, dst_imc_id,msg_vid, msg_subtype,
								chunk_create(msg, msg_len));
	result =receive_message(state, in_msg);
	in_msg->destroy(in_msg);

	return result;
}

/**
 * see section 3.8.7 of TCG TNC IF-IMC Specification 1.3
 */
TNC_Result TNC_IMC_API TNC_IMC_BatchEnding(TNC_IMCID imc_id,
										   TNC_ConnectionID connection_id)
{
	if (!imc_os)
	{
		DBG1(DBG_IMC, "IMC \"%s\" has not been initialized", imc_name);
		return TNC_RESULT_NOT_INITIALIZED;
	}
	return TNC_RESULT_SUCCESS;
}

/**
 * see section 3.8.8 of TCG TNC IF-IMC Specification 1.3
 */
TNC_Result TNC_IMC_API TNC_IMC_Terminate(TNC_IMCID imc_id)
{
	if (!imc_os)
	{
		DBG1(DBG_IMC, "IMC \"%s\" has not been initialized", imc_name);
		return TNC_RESULT_NOT_INITIALIZED;
	}
	imc_os->destroy(imc_os);
	imc_os = NULL;

	os->destroy(os);
	os = NULL;

	return TNC_RESULT_SUCCESS;
}

/**
 * see section 4.2.8.1 of TCG TNC IF-IMC Specification 1.3
 */
TNC_Result TNC_IMC_API TNC_IMC_ProvideBindFunction(TNC_IMCID imc_id,
									TNC_TNCC_BindFunctionPointer bind_function)
{
	if (!imc_os)
	{
		DBG1(DBG_IMC, "IMC \"%s\" has not been initialized", imc_name);
		return TNC_RESULT_NOT_INITIALIZED;
	}
	return imc_os->bind_functions(imc_os, bind_function);
}