/**
 * @file xml_interface.c
 * 
 * @brief Implementation of xml_interface_t.
 * 
 */

/*
 * Copyright (C) 2007 Martin Willi
 * 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 <stdlib.h>

#include "xml_interface.h"

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <unistd.h>
#include <errno.h>
#include <pthread.h>
#include <signal.h>
#include <libxml/xmlreader.h>
#include <libxml/xmlwriter.h>

#include <library.h>
#include <daemon.h>
#include <processing/jobs/callback_job.h>


typedef struct private_xml_interface_t private_xml_interface_t;

/**
 * Private data of an xml_interface_t object.
 */
struct private_xml_interface_t {

	/**
	 * Public part of xml_t object.
	 */
	xml_interface_t public;
	
	/**
	 * XML unix socket fd
	 */
	int socket;
	
	/**
	 * job accepting stroke messages
	 */
	callback_job_t *job;
};

ENUM(ike_sa_state_lower_names, IKE_CREATED, IKE_DELETING,
	"created",
	"connecting",
	"established",
	"rekeying",
	"deleting",
);

/**
 * write a bool into element
 */
static void write_bool(xmlTextWriterPtr writer, char *element, bool val)
{
	xmlTextWriterWriteElement(writer, element, val ? "true" : "false");
}

/**
 * write a identification_t into element
 */
static void write_id(xmlTextWriterPtr writer, char *element, identification_t *id)
{
	xmlTextWriterStartElement(writer, element);
	switch (id->get_type(id))
	{
		{
			char *type = "";
			while (TRUE)
			{
				case ID_ANY:
					type = "any";
					break;
				case ID_IPV4_ADDR:
					type = "ipv4";
					break;
				case ID_IPV6_ADDR:
					type = "ipv6";
					break;
				case ID_FQDN:
					type = "fqdn";
					break;
				case ID_RFC822_ADDR:
					type = "email";
					break;
				case ID_DER_ASN1_DN:
					type = "asn1dn";
					break;
				case ID_DER_ASN1_GN:
					type = "asn1gn";
					break;
			}
			xmlTextWriterWriteAttribute(writer, "type", type);
			xmlTextWriterWriteFormatString(writer, "%D", id);
			break;
		}
		default:
			/* TODO: base64 keyid */
			xmlTextWriterWriteAttribute(writer, "type", "keyid");
			break;
	}
	xmlTextWriterEndElement(writer);
}

/**
 * write a host_t address into an element
 */
static void write_address(xmlTextWriterPtr writer, char *element, host_t *host)
{
	xmlTextWriterStartElement(writer, element);
	xmlTextWriterWriteAttribute(writer, "type",
						host->get_family(host) == AF_INET ? "ipv4" : "ipv6");
	if (host->is_anyaddr(host))
	{	/* do not use %any for XML */
		xmlTextWriterWriteFormatString(writer, "%s",
						host->get_family(host) == AF_INET ? "0.0.0.0" : "::");
	}
	else
	{
		xmlTextWriterWriteFormatString(writer, "%H", host);
	}
	xmlTextWriterEndElement(writer);
}

/**
 * write networks element
 */
static void write_networks(xmlTextWriterPtr writer, char *element,
						   linked_list_t *list)
{
	iterator_t *iterator;
	traffic_selector_t *ts;
	
	xmlTextWriterStartElement(writer, element);
	iterator = list->create_iterator(list, TRUE);
	while (iterator->iterate(iterator, (void**)&ts))
	{
		xmlTextWriterStartElement(writer, "network");
		xmlTextWriterWriteAttribute(writer, "type",
						ts->get_type(ts) == TS_IPV4_ADDR_RANGE ? "ipv4" : "ipv6");
		xmlTextWriterWriteFormatString(writer, "%R", ts);
		xmlTextWriterEndElement(writer);
	}
	iterator->destroy(iterator);
	xmlTextWriterEndElement(writer);
}

/**
 * write a childEnd
 */
static void write_childend(xmlTextWriterPtr writer, child_sa_t *child, bool local)
{
	linked_list_t *list;
	
	xmlTextWriterWriteFormatElement(writer, "spi", "%lx", 
									htonl(child->get_spi(child, local)));
	list = child->get_traffic_selectors(child, local);
	write_networks(writer, "networks", list);
}

/**
 * write a child_sa_t 
 */
static void write_child(xmlTextWriterPtr writer, child_sa_t *child)
{
	mode_t mode;
	encryption_algorithm_t encr;
	integrity_algorithm_t int_algo;
	size_t encr_len, int_len;
	u_int32_t rekey, use_in, use_out, use_fwd;
	child_cfg_t *config;
	
	config = child->get_config(child);
	child->get_stats(child, &mode, &encr, &encr_len, &int_algo, &int_len,
					 &rekey, &use_in, &use_out, &use_fwd);

	xmlTextWriterStartElement(writer, "childsa");
	xmlTextWriterWriteFormatElement(writer, "reqid", "%d", child->get_reqid(child));
	xmlTextWriterWriteFormatElement(writer, "childconfig", "%s", 
									config->get_name(config));
	xmlTextWriterStartElement(writer, "local");
	write_childend(writer, child, TRUE);
	xmlTextWriterEndElement(writer);
	xmlTextWriterStartElement(writer, "remote");
	write_childend(writer, child, FALSE);
	xmlTextWriterEndElement(writer);
	xmlTextWriterEndElement(writer);
}

/**
 * process a ikesalist query request message
 */
static void request_query_ikesa(xmlTextReaderPtr reader, xmlTextWriterPtr writer)
{
	iterator_t *iterator;
	ike_sa_t *ike_sa;

	/* <ikesalist> */
	xmlTextWriterStartElement(writer, "ikesalist");
	
	iterator = charon->ike_sa_manager->create_iterator(charon->ike_sa_manager);
	while (iterator->iterate(iterator, (void**)&ike_sa))
	{
		ike_sa_id_t *id;
		host_t *local, *remote;
		iterator_t *children;
		child_sa_t *child_sa;
		
		id = ike_sa->get_id(ike_sa);
		
		xmlTextWriterStartElement(writer, "ikesa");
		xmlTextWriterWriteFormatElement(writer, "id", "%d",
							ike_sa->get_unique_id(ike_sa));
		xmlTextWriterWriteFormatElement(writer, "status", "%N", 
							ike_sa_state_lower_names, ike_sa->get_state(ike_sa));
		xmlTextWriterWriteElement(writer, "role",
							id->is_initiator(id) ? "initiator" : "responder");
		xmlTextWriterWriteElement(writer, "peerconfig", ike_sa->get_name(ike_sa));
		
		/* <local> */
		local = ike_sa->get_my_host(ike_sa);
		xmlTextWriterStartElement(writer, "local");
		xmlTextWriterWriteFormatElement(writer, "spi", "%.16llx",
							id->is_initiator(id) ? id->get_initiator_spi(id)
												 : id->get_responder_spi(id));
		write_id(writer, "identification", ike_sa->get_my_id(ike_sa));
		write_address(writer, "address", local);
		xmlTextWriterWriteFormatElement(writer, "port", "%d",
							local->get_port(local));
		if (ike_sa->supports_extension(ike_sa, EXT_NATT))
		{
			write_bool(writer, "nat", ike_sa->has_condition(ike_sa, COND_NAT_HERE));
		}
		xmlTextWriterEndElement(writer);
		/* </local> */
		
		/* <remote> */
		remote = ike_sa->get_other_host(ike_sa);
		xmlTextWriterStartElement(writer, "remote");
		xmlTextWriterWriteFormatElement(writer, "spi", "%.16llx",
							id->is_initiator(id) ? id->get_responder_spi(id)
												 : id->get_initiator_spi(id));
		write_id(writer, "identification", ike_sa->get_other_id(ike_sa));
		write_address(writer, "address", remote);
		xmlTextWriterWriteFormatElement(writer, "port", "%d",
							remote->get_port(remote));
		if (ike_sa->supports_extension(ike_sa, EXT_NATT))
		{
			write_bool(writer, "nat", ike_sa->has_condition(ike_sa, COND_NAT_THERE));
		}
		xmlTextWriterEndElement(writer);
		/* </remote> */		
		
		/* <childsalist> */
		xmlTextWriterStartElement(writer, "childsalist");
		children = ike_sa->create_child_sa_iterator(ike_sa);
		while (children->iterate(children, (void**)&child_sa))
		{
			write_child(writer, child_sa);
		}
		children->destroy(children);
		/* </childsalist> */
		xmlTextWriterEndElement(writer);		
		
		/* </ikesa> */
		xmlTextWriterEndElement(writer);
	}
	iterator->destroy(iterator);
	
	/* </ikesalist> */
	xmlTextWriterEndElement(writer);
}

/**
 * process a configlist query request message
 */
static void request_query_config(xmlTextReaderPtr reader, xmlTextWriterPtr writer)
{
	iterator_t *iterator;
	peer_cfg_t *peer_cfg;

	/* <configlist> */
	xmlTextWriterStartElement(writer, "configlist");
	
	iterator = charon->backends->create_iterator(charon->backends);
	while (iterator->iterate(iterator, (void**)&peer_cfg))
	{
		iterator_t *children;
		child_cfg_t *child_cfg;
		ike_cfg_t *ike_cfg;
		linked_list_t *list;
		
		if (peer_cfg->get_ike_version(peer_cfg) != 2)
		{	/* only IKEv2 connections yet */
			continue;
		}
		
		/* <peerconfig> */
		xmlTextWriterStartElement(writer, "peerconfig");
		xmlTextWriterWriteElement(writer, "name", peer_cfg->get_name(peer_cfg));
		write_id(writer, "local", peer_cfg->get_my_id(peer_cfg));
		write_id(writer, "remote", peer_cfg->get_other_id(peer_cfg));
		
		/* <ikeconfig> */
		ike_cfg = peer_cfg->get_ike_cfg(peer_cfg);
		xmlTextWriterStartElement(writer, "ikeconfig");
		write_address(writer, "local", ike_cfg->get_my_host(ike_cfg));
		write_address(writer, "remote", ike_cfg->get_other_host(ike_cfg));
		xmlTextWriterEndElement(writer);
		/* </ikeconfig> */
		
		/* <childconfiglist> */
		xmlTextWriterStartElement(writer, "childconfiglist");
		children = peer_cfg->create_child_cfg_iterator(peer_cfg);
		while (children->iterate(children, (void**)&child_cfg))
		{
			/* <childconfig> */
			xmlTextWriterStartElement(writer, "childconfig");		
			xmlTextWriterWriteElement(writer, "name",
									  child_cfg->get_name(child_cfg));
			list = child_cfg->get_traffic_selectors(child_cfg, TRUE, NULL, NULL);
			write_networks(writer, "local", list);
			list->destroy_offset(list, offsetof(traffic_selector_t, destroy));
			list = child_cfg->get_traffic_selectors(child_cfg, FALSE, NULL, NULL);
			write_networks(writer, "remote", list);
			list->destroy_offset(list, offsetof(traffic_selector_t, destroy));		
			xmlTextWriterEndElement(writer);
			/* </childconfig> */
		}
		children->destroy(children);
		/* </childconfiglist> */
		xmlTextWriterEndElement(writer);
		/* </peerconfig> */
		xmlTextWriterEndElement(writer);	
	}
	iterator->destroy(iterator);
	/* </configlist> */
	xmlTextWriterEndElement(writer);
}

/**
 * callback which logs to a XML writer
 */
static bool xml_callback(xmlTextWriterPtr writer, signal_t signal, level_t level,
						 ike_sa_t* ike_sa, char* format, va_list args)
{
	if (level <= 1)
	{
		/* <item> */
		xmlTextWriterStartElement(writer, "item");
		xmlTextWriterWriteFormatAttribute(writer, "level", "%d", level);
		xmlTextWriterWriteFormatAttribute(writer, "source", "%N", signal_names, signal);
		xmlTextWriterWriteFormatAttribute(writer, "thread", "%u", pthread_self());
		xmlTextWriterWriteVFormatString(writer, format, args);
		xmlTextWriterEndElement(writer);
		/* </item> */
	}
	return TRUE;
}

/**
 * process a *terminate control request message
 */
static void request_control_terminate(xmlTextReaderPtr reader,
									  xmlTextWriterPtr writer, bool ike)
{
	if (xmlTextReaderRead(reader) &&
		xmlTextReaderNodeType(reader) == XML_READER_TYPE_TEXT)
	{
		const char *str;
		u_int32_t id;
		status_t status;
	
		str = xmlTextReaderConstValue(reader);
		if (str == NULL || !(id = atoi(str)))
		{
			DBG1(DBG_CFG, "error parsing XML id string");
			return;
		}
		DBG1(DBG_CFG, "terminating %s_SA %d", ike ? "IKE" : "CHILD", id);
		
		/* <log> */
		xmlTextWriterStartElement(writer, "log");
		if (ike)
		{
			status = charon->interfaces->terminate_ike(
					charon->interfaces,	id, 
					(interface_manager_cb_t)xml_callback, writer);
		}
		else
		{
			status = charon->interfaces->terminate_child(
					charon->interfaces,	id, 
					(interface_manager_cb_t)xml_callback, writer);
		}
		/* </log> */
		xmlTextWriterEndElement(writer);
		xmlTextWriterWriteFormatElement(writer, "status", "%d", status);
	}
}

/**
 * process a *initiate control request message
 */
static void request_control_initiate(xmlTextReaderPtr reader,
									  xmlTextWriterPtr writer, bool ike)
{
	if (xmlTextReaderRead(reader) &&
		xmlTextReaderNodeType(reader) == XML_READER_TYPE_TEXT)
	{
		const char *str;
		status_t status = FAILED;
		peer_cfg_t *peer;
		child_cfg_t *child = NULL;
		iterator_t *iterator;
			
		str = xmlTextReaderConstValue(reader);
		if (str == NULL)
		{
			DBG1(DBG_CFG, "error parsing XML config name string");
			return;
		}
		DBG1(DBG_CFG, "initiating %s_SA %s", ike ? "IKE" : "CHILD", str);
		
		/* <log> */
		xmlTextWriterStartElement(writer, "log");
		peer = charon->backends->get_peer_cfg_by_name(charon->backends, (char*)str);
		if (peer)
		{
			iterator = peer->create_child_cfg_iterator(peer);
			if (ike)
			{
				if (!iterator->iterate(iterator, (void**)&child))
				{
					child = NULL;
				}
				child->get_ref(child);
			}
			else
			{
				while (iterator->iterate(iterator, (void**)&child))
				{
					if (streq(child->get_name(child), str))
					{
						child->get_ref(child);
						break;
					}
					child = NULL;
				}
			}
			iterator->destroy(iterator);
			if (child)
			{
				status = charon->interfaces->initiate(charon->interfaces,
							peer, child, (interface_manager_cb_t)xml_callback,
							writer);
			}
			else
			{
				peer->destroy(peer);
			}
		}
		/* </log> */
		xmlTextWriterEndElement(writer);
		xmlTextWriterWriteFormatElement(writer, "status", "%d", status);
	}
}

/**
 * process a query request
 */
static void request_query(xmlTextReaderPtr reader, xmlTextWriterPtr writer)
{
	/* <query> */
	xmlTextWriterStartElement(writer, "query");
    while (xmlTextReaderRead(reader))
    {
		if (xmlTextReaderNodeType(reader) == XML_READER_TYPE_ELEMENT)
		{
			if (streq(xmlTextReaderConstName(reader), "ikesalist"))
			{
				request_query_ikesa(reader, writer);
				break;
			}
			if (streq(xmlTextReaderConstName(reader), "configlist"))
			{
				request_query_config(reader, writer);
				break;
			}
		}
	}
	/* </query> */
	xmlTextWriterEndElement(writer);
}

/**
 * process a control request
 */
static void request_control(xmlTextReaderPtr reader, xmlTextWriterPtr writer)
{
	/* <control> */
	xmlTextWriterStartElement(writer, "control");
    while (xmlTextReaderRead(reader))
    {
		if (xmlTextReaderNodeType(reader) == XML_READER_TYPE_ELEMENT)
		{
			if (streq(xmlTextReaderConstName(reader), "ikesaterminate"))
			{
				request_control_terminate(reader, writer, TRUE);
				break;
			}
			if (streq(xmlTextReaderConstName(reader), "childsaterminate"))
			{
				request_control_terminate(reader, writer, FALSE);
				break;
			}
			if (streq(xmlTextReaderConstName(reader), "ikesainitiate"))
			{
				request_control_initiate(reader, writer, TRUE);
				break;
			}
			if (streq(xmlTextReaderConstName(reader), "childsainitiate"))
			{
				request_control_initiate(reader, writer, FALSE);
				break;
			}
		}
	}
	/* </control> */
	xmlTextWriterEndElement(writer);
}

/**
 * process a request message
 */
static void request(xmlTextReaderPtr reader, char *id, int fd)
{
	xmlTextWriterPtr writer;
	
	writer = xmlNewTextWriter(xmlOutputBufferCreateFd(fd, NULL));
	if (writer == NULL)
	{
		DBG1(DBG_CFG, "opening SMP XML writer failed");
		return;
	}

	xmlTextWriterStartDocument(writer, NULL, NULL, NULL);
	/* <message xmlns="http://www.strongswan.org/smp/1.0"
		id="id" type="response"> */
	xmlTextWriterStartElement(writer, "message");
	xmlTextWriterWriteAttribute(writer, "xmlns",
								"http://www.strongswan.org/smp/1.0");
	xmlTextWriterWriteAttribute(writer, "id", id);
	xmlTextWriterWriteAttribute(writer, "type", "response");

	while (xmlTextReaderRead(reader))
	{
		if (xmlTextReaderNodeType(reader) == XML_READER_TYPE_ELEMENT)
		{
			if (streq(xmlTextReaderConstName(reader), "query"))
			{
				request_query(reader, writer);
				break;
			}
			if (streq(xmlTextReaderConstName(reader), "control"))
			{
				request_control(reader, writer);
				break;
			}
		}
	}
	/*   </message> and close document */
	xmlTextWriterEndDocument(writer);
	xmlFreeTextWriter(writer);
}

/**
 * cleanup helper function for open file descriptors
 */
static void closefdp(int *fd)
{
	close(*fd);
}

/**
 * read from a opened connection and process it
 */
static job_requeue_t process(int *fdp)
{
	int oldstate, fd = *fdp;
	char buffer[4096];
	size_t len;
	xmlTextReaderPtr reader;
	char *id = NULL, *type = NULL;
	
	pthread_cleanup_push((void*)closefdp, (void*)&fd);
	pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, &oldstate);
	len = read(fd, buffer, sizeof(buffer));
	pthread_setcancelstate(oldstate, NULL);
	pthread_cleanup_pop(0);
	if (len <= 0)
	{
		close(fd);
		DBG2(DBG_CFG, "SMP XML connection closed");
		return JOB_REQUEUE_NONE;
	}
	DBG3(DBG_CFG, "got XML request: %b", buffer, len);
	
	reader = xmlReaderForMemory(buffer, len, NULL, NULL, 0);
	if (reader == NULL)
	{
		DBG1(DBG_CFG, "opening SMP XML reader failed");
		return JOB_REQUEUE_FAIR;;
	}
	
	/* read message type and id */
    while (xmlTextReaderRead(reader))
    {
		if (xmlTextReaderNodeType(reader) == XML_READER_TYPE_ELEMENT &&
			streq(xmlTextReaderConstName(reader), "message"))
		{
			id = xmlTextReaderGetAttribute(reader, "id");
			type = xmlTextReaderGetAttribute(reader, "type");
			break;
		}
    }
    
    /* process message */
    if (id && type)
	{
	    if (streq(type, "request"))
	    {
	    	request(reader, id, fd);
	    }
	    else
	    {
	    	/* response(reader, id) */
	    }
    }
	xmlFreeTextReader(reader);
	return JOB_REQUEUE_FAIR;;
}

/**
 * accept from XML socket and create jobs to process connections
 */
static job_requeue_t dispatch(private_xml_interface_t *this)
{
	struct sockaddr_un strokeaddr;
	int oldstate, fd, *fdp, strokeaddrlen = sizeof(strokeaddr);
	callback_job_t *job;
	
	/* wait for connections, but allow thread to terminate */
	pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, &oldstate);
	fd = accept(this->socket, (struct sockaddr *)&strokeaddr, &strokeaddrlen);
	pthread_setcancelstate(oldstate, NULL);
	
	if (fd < 0)
	{
		DBG1(DBG_CFG, "accepting SMP XML socket failed: %s", strerror(errno));
		sleep(1);
		return JOB_REQUEUE_FAIR;;
	}
	
	fdp = malloc_thing(int);
	*fdp = fd;
	job = callback_job_create((callback_job_cb_t)process, fdp, free, this->job);
	charon->processor->queue_job(charon->processor, (job_t*)job);
	
	return JOB_REQUEUE_DIRECT;
}

/**
 * Implementation of itnerface_t.destroy.
 */
static void destroy(private_xml_interface_t *this)
{
	this->job->cancel(this->job);
	close(this->socket);
	free(this);
}

/*
 * Described in header file
 */
interface_t *interface_create()
{
	struct sockaddr_un unix_addr = { AF_UNIX, IPSEC_PIDDIR "/charon.xml"};
	private_xml_interface_t *this = malloc_thing(private_xml_interface_t);
	mode_t old;

	this->public.interface.destroy = (void (*)(interface_t*))destroy;
	
	/* set up unix socket */
	this->socket = socket(AF_UNIX, SOCK_STREAM, 0);
	if (this->socket == -1)
	{
		DBG1(DBG_CFG, "could not create XML socket");
		free(this);
		return NULL;
	}
	
	unlink(unix_addr.sun_path);
	old = umask(~(S_IRWXU | S_IRWXG));
	if (bind(this->socket, (struct sockaddr *)&unix_addr, sizeof(unix_addr)) < 0)
	{
		DBG1(DBG_CFG, "could not bind XML socket: %s", strerror(errno));
		close(this->socket);
		free(this);
		return NULL;
	}
	umask(old);
	if (chown(unix_addr.sun_path, IPSEC_UID, IPSEC_GID) != 0)
	{
		DBG1(DBG_CFG, "changing XML socket permissions failed: %s", strerror(errno));
	}
	
	if (listen(this->socket, 5) < 0)
	{
		DBG1(DBG_CFG, "could not listen on XML socket: %s", strerror(errno));
		close(this->socket);
		free(this);
		return NULL;
	}

	this->job = callback_job_create((callback_job_cb_t)dispatch, this, NULL, NULL);
	charon->processor->queue_job(charon->processor, (job_t*)this->job);
	
	return &this->public.interface;
}