src/mod_netconf.c

/*!
 * \file mod_netconf.c
 * \brief NETCONF Apache modul for Netopeer
 * \author Tomas Cejka <cejkat@cesnet.cz>
 * \author Radek Krejci <rkrejci@cesnet.cz>
 * \date 2011
 * \date 2012
 * \date 2013
 */
/*
 * Copyright (C) 2011-2012 CESNET
 *
 * LICENSE TERMS
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name of the Company nor the names of its contributors
 *    may be used to endorse or promote products derived from this
 *    software without specific prior written permission.
 *
 * ALTERNATIVELY, provided that this notice is retained in full, this
 * product may be distributed under the terms of the GNU General Public
 * License (GPL) version 2 or later, in which case the provisions
 * of the GPL apply INSTEAD OF those given above.
 *
 * This software is provided ``as is'', and any express or implied
 * warranties, including, but not limited to, the implied warranties of
 * merchantability and fitness for a particular purpose are disclaimed.
 * In no event shall the company or contributors be liable for any
 * direct, indirect, incidental, special, exemplary, or consequential
 * damages (including, but not limited to, procurement of substitute
 * goods or services; loss of use, data, or profits; or business
 * interruption) however caused and on any theory of liability, whether
 * in contract, strict liability, or tort (including negligence or
 * otherwise) arising in any way out of the use of this software, even
 * if advised of the possibility of such damage.
 *
 */
static const char rcsid[] __attribute__((used)) ="$Id: "__FILE__": "ARCSID" $";

#include <unistd.h>
#include <poll.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <pthread.h>
#include <ctype.h>

#include <unixd.h>
#include <httpd.h>
#include <http_log.h>
#include <http_config.h>

#include <apr_sha1.h>
#include <apr_hash.h>
#include <apr_signal.h>
#include <apr_strings.h>

#include <json/json.h>

#include <libnetconf.h>

#include "message_type.h"


#define MAX_PROCS 5
#define SOCKET_FILENAME "/tmp/mod_netconf.sock"
#define MAX_SOCKET_CL 10
#define BUFFER_SIZE 4096

/* sleep in master process for non-blocking socket reading */
#define SLEEP_TIME 200

#ifndef offsetof
#define offsetof(type, member) ((size_t) ((type *) 0)->member)
#endif

/* timeout in msec */
struct timeval timeout = { 1, 0 };

#define NCWITHDEFAULTS	NCWD_MODE_NOTSET



#define MSG_OK 0
#define MSG_OPEN  1
#define MSG_DATA  2
#define MSG_CLOSE 3
#define MSG_ERROR 4
#define MSG_UNKNOWN 5

module AP_MODULE_DECLARE_DATA netconf_module;

typedef struct {
	apr_pool_t *pool;
	apr_proc_t *forkproc;
	char* sockname;
} mod_netconf_cfg;

struct pass_to_thread {
	int client; /**< opened socket */
	apr_pool_t * pool; /**< ?? */
	server_rec * server; /**< ?? */
	apr_hash_t * netconf_sessions_list; /**< ?? */
};

struct session_with_mutex {
	struct nc_session * session; /**< netconf session */
	pthread_mutex_t lock; /**< mutex protecting the session from multiple access */
};

pthread_rwlock_t session_lock; /**< mutex protecting netconf_session_list from multiple access errors */

volatile int isterminated = 0;

static char* password;


static void signal_handler(int sign)
{
	switch (sign) {
	case SIGTERM:
		isterminated = 1;
		break;
	}
}

static char* gen_ncsession_hash( const char* hostname, const char* port, const char* sid)
{
	unsigned char hash_raw[APR_SHA1_DIGESTSIZE];
	int i;
	char* hash;

	apr_sha1_ctx_t sha1_ctx;
	apr_sha1_init(&sha1_ctx);
	apr_sha1_update(&sha1_ctx, hostname, strlen(hostname));
	apr_sha1_update(&sha1_ctx, port, strlen(port));
	apr_sha1_update(&sha1_ctx, sid, strlen(sid));
	apr_sha1_final(hash_raw, &sha1_ctx);

	/* convert binary hash into hex string, which is printable */
	hash = malloc(sizeof(char) * ((2*APR_SHA1_DIGESTSIZE)+1));
	for (i = 0; i < APR_SHA1_DIGESTSIZE; i++) {
		snprintf(hash + (2*i), 3, "%02x", hash_raw[i]);
	}
	//hash[2*APR_SHA1_DIGESTSIZE] = 0;

	return (hash);
}

int netconf_callback_ssh_hostkey_check (const char* hostname, int keytype, const char* fingerprint)
{
	/* always approve */
	return (EXIT_SUCCESS);
}

char* netconf_callback_sshauth_password (const char* username, const char* hostname)
{
	char* buf;

	buf = malloc ((strlen(password) + 1) * sizeof(char));
	apr_cpystrn(buf, password, strlen(password) + 1);

	return (buf);
}

void netconf_callback_sshauth_interactive (const char* name,
		int name_len,
		const char* instruction,
		int instruction_len,
		int num_prompts,
		const LIBSSH2_USERAUTH_KBDINT_PROMPT* prompts,
		LIBSSH2_USERAUTH_KBDINT_RESPONSE* responses,
		void** abstract)
{
	int i;

	for (i=0; i<num_prompts; i++) {
		responses[i].text = malloc ((strlen(password) + 1) * sizeof(char));
		apr_cpystrn(responses[i].text, password, strlen(password) + 1);
		responses[i].length = strlen(responses[i].text) + 1;
	}

	return;
}

static json_object *err_reply = NULL;
void netconf_callback_error_process(const char* tag,
		const char* type,
		const char* severity,
		const char* apptag,
		const char* path,
		const char* message,
		const char* attribute,
		const char* element,
		const char* ns,
		const char* sid)
{
	err_reply = json_object_new_object();
	json_object_object_add(err_reply, "type", json_object_new_int(REPLY_ERROR));
	if (tag) json_object_object_add(err_reply, "error-tag", json_object_new_string(tag));
	if (type) json_object_object_add(err_reply, "error-type", json_object_new_string(type));
	if (severity) json_object_object_add(err_reply, "error-severity", json_object_new_string(severity));
	if (apptag) json_object_object_add(err_reply, "error-app-tag", json_object_new_string(apptag));
	if (path) json_object_object_add(err_reply, "error-path", json_object_new_string(path));
	if (message) json_object_object_add(err_reply, "error-message", json_object_new_string(message));
	if (attribute) json_object_object_add(err_reply, "bad-attribute", json_object_new_string(attribute));
	if (element) json_object_object_add(err_reply, "bad-element", json_object_new_string(element));
	if (ns) json_object_object_add(err_reply, "bad-namespace", json_object_new_string(ns));
	if (sid) json_object_object_add(err_reply, "session-id", json_object_new_string(sid));
}

static char* netconf_connect(server_rec* server, apr_pool_t* pool, apr_hash_t* conns, const char* host, const char* port, const char* user, const char* pass, struct nc_cpblts * cpblts)
{
	struct nc_session* session;
	struct session_with_mutex * locked_session;
	char *session_key;

	/* connect to the requested NETCONF server */
	password = (char*)pass;
	session = nc_session_connect(host, (unsigned short) atoi (port), user, cpblts);

	/* if connected successful, add session to the list */
	if (session != NULL) {
		/* generate hash for the session */
		session_key = gen_ncsession_hash(
				(host==NULL) ? "localhost" : host,
				(port==NULL) ? "830" : port,
				nc_session_get_id(session));

		if ((locked_session = malloc (sizeof (struct session_with_mutex))) == NULL || pthread_mutex_init (&locked_session->lock, NULL) != 0) {
			nc_session_free(session);
			free (locked_session);
			ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "Creating structure session_with_mutex failed %d (%s)", errno, strerror(errno));
			return NULL;
		}
		locked_session->session = session;
		pthread_mutex_init (&locked_session->lock, NULL);
		ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, server, "Before session_lock");
		/* get exclusive access to sessions_list (conns) */
		if (pthread_rwlock_wrlock (&session_lock) != 0) {
			nc_session_free(session);
			free (locked_session);
			ap_log_error (APLOG_MARK, APLOG_ERR, 0, server, "Error while locking rwlock: %d (%s)", errno, strerror(errno));
			return NULL;
		}
		ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, server, "Add connection to the list");
		apr_hash_set(conns, apr_pstrdup(pool, session_key), APR_HASH_KEY_STRING, (void *) locked_session);
		ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, server, "Before session_unlock");
		/* end of critical section */
		if (pthread_rwlock_unlock (&session_lock) != 0) {
			ap_log_error (APLOG_MARK, APLOG_ERR, 0, server, "Error while unlocking rwlock: %d (%s)", errno, strerror(errno));
			return NULL;
		}
		ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, server, "NETCONF session established");
		return (session_key);
	} else {
		ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "Connection could not be established");
		return (NULL);
	}

}

static int netconf_close(server_rec* server, apr_hash_t* conns, const char* session_key)
{
	struct nc_session *ns = NULL;
	struct session_with_mutex * locked_session;

	ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, server, "Key in hash to get: %s", session_key);
	/* get exclusive (write) access to sessions_list (conns) */
	if (pthread_rwlock_wrlock (&session_lock) != 0) {
		ap_log_error (APLOG_MARK, APLOG_ERR, 0, server, "Error while locking rwlock: %d (%s)", errno, strerror(errno));
		return EXIT_FAILURE;
	}
	locked_session = (struct session_with_mutex *)apr_hash_get(conns, session_key, APR_HASH_KEY_STRING);
	if (locked_session != NULL) {
		pthread_mutex_destroy(&locked_session->lock);
		ns = locked_session->session;
		free (locked_session);
	}
	if (ns != NULL) {
		nc_session_close (ns, NC_SESSION_TERM_CLOSED);
		nc_session_free (ns);
		ns = NULL;

		/* remove session from the active sessions list */
		apr_hash_set(conns, session_key, APR_HASH_KEY_STRING, NULL);
		/* end of critical section */
		if (pthread_rwlock_unlock (&session_lock) != 0) {
			ap_log_error (APLOG_MARK, APLOG_ERR, 0, server, "Error while unlocking rwlock: %d (%s)", errno, strerror(errno));
			return EXIT_FAILURE;
		}
		ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, server, "NETCONF session closed");

		return (EXIT_SUCCESS);
	} else {
		if (pthread_rwlock_unlock (&session_lock) != 0) {
			ap_log_error (APLOG_MARK, APLOG_ERR, 0, server, "Error while unlocking rwlock: %d (%s)", errno, strerror(errno));
			return EXIT_FAILURE;
		}
		ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "Unknown session to close");
		return (EXIT_FAILURE);
	}
}

static int netconf_op(server_rec* server, apr_hash_t* conns, const char* session_key, nc_rpc* rpc)
{
	struct nc_session *session = NULL;
	struct session_with_mutex * locked_session;
	nc_reply* reply;
	int retval = EXIT_SUCCESS;
	NC_MSG_TYPE msgt;
	NC_REPLY_TYPE replyt;

	/* check requests */
	if (rpc == NULL) {
		ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "mod_netconf: rpc is not created");
		return (EXIT_FAILURE);
	}

	/* get non-exclusive (read) access to sessions_list (conns) */
	if (pthread_rwlock_rdlock (&session_lock) != 0) {
		ap_log_error (APLOG_MARK, APLOG_ERR, 0, server, "Error while locking rwlock: %d (%s)", errno, strerror(errno));
		return EXIT_FAILURE;
	}
	/* get session where send the RPC */
	locked_session = (struct session_with_mutex *)apr_hash_get(conns, session_key, APR_HASH_KEY_STRING);
	if (locked_session != NULL) {
		session = locked_session->session;
	}
	if (session != NULL) {
		/* get exclusive access to session */
		if (pthread_mutex_lock(&locked_session->lock) != 0) {
			/* unlock before returning error */
			if (pthread_rwlock_unlock (&session_lock) != 0) {
				ap_log_error (APLOG_MARK, APLOG_ERR, 0, server, "Error while locking rwlock: %d (%s)", errno, strerror(errno));
				return EXIT_FAILURE;
			}
			return EXIT_FAILURE;
		}
		/* send the request and get the reply */
		msgt = nc_session_send_recv(session, rpc, &reply);

		/* first release exclusive lock for this session */
		pthread_mutex_unlock(&locked_session->lock);
		/* end of critical section */
		if (pthread_rwlock_unlock (&session_lock) != 0) {
			ap_log_error (APLOG_MARK, APLOG_ERR, 0, server, "Error while unlocking rwlock: %d (%s)", errno, strerror(errno));
			return EXIT_FAILURE;
		}

		/* process the result of the operation */
		switch (msgt) {
		case NC_MSG_UNKNOWN:
			if (nc_session_get_status(session) != NC_SESSION_STATUS_WORKING) {
				ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "mod_netconf: receiving rpc-reply failed");
				netconf_close(server, conns, session_key);
				return (EXIT_FAILURE);
			}
			/* no break */
		case NC_MSG_NONE:
			/* there is error handled by callback */
			return (EXIT_FAILURE);
			break;
		case NC_MSG_REPLY:
			switch (replyt = nc_reply_get_type(reply)) {
			case NC_REPLY_OK:
				retval = EXIT_SUCCESS;
				break;
			default:
				ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "mod_netconf: unexpected rpc-reply (%d)", replyt);
				retval = EXIT_FAILURE;
				break;
			}
			break;
		default:
			ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "mod_netconf: unexpected reply message received (%d)", msgt);
			retval = EXIT_FAILURE;
			break;
		}
		nc_reply_free(reply);
		return (retval);
	} else {
		/* release lock on failure */
		if (pthread_rwlock_unlock (&session_lock) != 0) {
			ap_log_error (APLOG_MARK, APLOG_ERR, 0, server, "Error while unlocking rwlock: %d (%s)", errno, strerror(errno));
		}
		ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "Unknown session to process.");
		return (EXIT_FAILURE);
	}
}

static char* netconf_opdata(server_rec* server, apr_hash_t* conns, const char* session_key, nc_rpc* rpc)
{
	struct nc_session *session = NULL;
	struct session_with_mutex * locked_session;
	nc_reply* reply = NULL;
	char* data;
	NC_MSG_TYPE msgt;
	NC_REPLY_TYPE replyt;

	/* check requests */
	if (rpc == NULL) {
		ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "mod_netconf: rpc is not created");
		return (NULL);
	}

	/* get non-exclusive (read) access to sessions_list (conns) */
	if (pthread_rwlock_rdlock (&session_lock) != 0) {
		ap_log_error (APLOG_MARK, APLOG_ERR, 0, server, "Error while locking rwlock: %d (%s)", errno, strerror(errno));
		return NULL;
	}
	/* get session where send the RPC */
	locked_session = (struct session_with_mutex *)apr_hash_get(conns, session_key, APR_HASH_KEY_STRING);
	if (locked_session != NULL) {
		session = locked_session->session;
	}
	if (session != NULL) {
		/* get exclusive access to session */
		if (pthread_mutex_lock(&locked_session->lock) != 0) {
			/* unlock before returning error */
			if (pthread_rwlock_unlock (&session_lock) != 0) {
				ap_log_error (APLOG_MARK, APLOG_ERR, 0, server, "Error while locking rwlock: %d (%s)", errno, strerror(errno));
				return NULL;
			}
			return NULL;
		}
		/* send the request and get the reply */
		msgt = nc_session_send_recv(session, rpc, &reply);

		/* first release exclusive lock for this session */
		pthread_mutex_unlock(&locked_session->lock);
		/* end of critical section */
		if (pthread_rwlock_unlock (&session_lock) != 0) {
			ap_log_error (APLOG_MARK, APLOG_ERR, 0, server, "Error while unlocking rwlock: %d (%s)", errno, strerror(errno));
			return (NULL);
		}

		/* process the result of the operation */
		switch (msgt) {
		case NC_MSG_UNKNOWN:
			if (nc_session_get_status(session) != NC_SESSION_STATUS_WORKING) {
				ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "mod_netconf: receiving rpc-reply failed");
				netconf_close(server, conns, session_key);
				return (NULL);
			}
			/* no break */
		case NC_MSG_NONE:
			/* there is error handled by callback */
			return (NULL);
			break;
		case NC_MSG_REPLY:
			switch (replyt = nc_reply_get_type(reply)) {
			case NC_REPLY_DATA:
				if ((data = nc_reply_get_data (reply)) == NULL) {
					ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "mod_netconf: no data from reply");
					data = NULL;
				}
				break;
			default:
				ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "mod_netconf: unexpected rpc-reply (%d)", replyt);
				data = NULL;
				break;
			}
			break;
		default:
			ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "mod_netconf: unexpected reply message received (%d)", msgt);
			data = NULL;
			break;
		}
		nc_reply_free(reply);
		return (data);
	} else {
		/* release lock on failure */
		if (pthread_rwlock_unlock (&session_lock) != 0) {
			ap_log_error (APLOG_MARK, APLOG_ERR, 0, server, "Error while unlocking rwlock: %d (%s)", errno, strerror(errno));
		}
		ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "Unknown session to process.");
		return (NULL);
	}
}

static char* netconf_getconfig(server_rec* server, apr_hash_t* conns, const char* session_key, NC_DATASTORE source, const char* filter)
{
	nc_rpc* rpc;
	struct nc_filter *f = NULL;
	char* data = NULL;

	/* create filter if set */
	if (filter != NULL) {
		f = nc_filter_new(NC_FILTER_SUBTREE, filter);
	}

	/* create requests */
	rpc = nc_rpc_getconfig (source, f);
	nc_filter_free(f);
	if (rpc == NULL) {
		ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "mod_netconf: creating rpc request failed");
		return (NULL);
	}

	data = netconf_opdata(server, conns, session_key, rpc);
	nc_rpc_free (rpc);
	return (data);
}

static char* netconf_getschema(server_rec* server, apr_hash_t* conns, const char* session_key, const char* identifier, const char* version, const char* format)
{
	nc_rpc* rpc;
	char* data = NULL;

	/* create requests */
	rpc = nc_rpc_getschema(identifier, version, format);
	if (rpc == NULL) {
		ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "mod_netconf: creating rpc request failed");
		return (NULL);
	}

	data = netconf_opdata(server, conns, session_key, rpc);
	nc_rpc_free (rpc);
	return (data);
}

static char* netconf_get(server_rec* server, apr_hash_t* conns, const char* session_key, const char* filter)
{
	nc_rpc* rpc;
	struct nc_filter *f = NULL;
	char* data = NULL;

	/* create filter if set */
	if (filter != NULL) {
		f = nc_filter_new(NC_FILTER_SUBTREE, filter);
	}

	/* create requests */
	rpc = nc_rpc_get (f);
	nc_filter_free(f);
	if (rpc == NULL) {
		ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "mod_netconf: creating rpc request failed");
		return (NULL);
	}

	data = netconf_opdata(server, conns, session_key, rpc);
	nc_rpc_free (rpc);
	return (data);
}

static int netconf_copyconfig(server_rec* server, apr_hash_t* conns, const char* session_key, NC_DATASTORE source, NC_DATASTORE target, const char* config, const char *url)
{
	nc_rpc* rpc;
	int retval = EXIT_SUCCESS;

	/* create requests */
	if ((source == NC_DATASTORE_CONFIG) || (source == NC_DATASTORE_URL)) {
		if (target == NC_DATASTORE_URL) {
			rpc = nc_rpc_copyconfig(source, target, config, url);
		} else {
			rpc = nc_rpc_copyconfig(source, target, config);
		}
	} else {
		if (target == NC_DATASTORE_URL) {
			rpc = nc_rpc_copyconfig(source, target, url);
		} else {
			rpc = nc_rpc_copyconfig(source, target);
		}
	}
	if (rpc == NULL) {
		ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "mod_netconf: creating rpc request failed");
		return (EXIT_FAILURE);
	}

	retval = netconf_op(server, conns, session_key, rpc);
	nc_rpc_free (rpc);
	return (retval);
}

static int netconf_editconfig(server_rec* server, apr_hash_t* conns, const char* session_key, NC_DATASTORE target, NC_EDIT_DEFOP_TYPE defop, NC_EDIT_ERROPT_TYPE erropt, NC_EDIT_TESTOPT_TYPE testopt, const char* config)
{
	nc_rpc* rpc;
	int retval = EXIT_SUCCESS;

	/* create requests */
	/* TODO source NC_DATASTORE_CONFIG / NC_DATASTORE_URL  */
	rpc = nc_rpc_editconfig(target, NC_DATASTORE_CONFIG, defop, erropt, testopt, config);
	if (rpc == NULL) {
		ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "mod_netconf: creating rpc request failed");
		return (EXIT_FAILURE);
	}

	retval = netconf_op(server, conns, session_key, rpc);
	nc_rpc_free (rpc);
	return (retval);
}

static int netconf_killsession(server_rec* server, apr_hash_t* conns, const char* session_key, const char* sid)
{
	nc_rpc* rpc;
	int retval = EXIT_SUCCESS;

	/* create requests */
	rpc = nc_rpc_killsession(sid);
	if (rpc == NULL) {
		ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "mod_netconf: creating rpc request failed");
		return (EXIT_FAILURE);
	}

	retval = netconf_op(server, conns, session_key, rpc);
	nc_rpc_free (rpc);
	return (retval);
}

static int netconf_onlytargetop(server_rec* server, apr_hash_t* conns, const char* session_key, NC_DATASTORE target, nc_rpc* (*op_func)(NC_DATASTORE))
{
	nc_rpc* rpc;
	int retval = EXIT_SUCCESS;

	/* create requests */
	rpc = op_func(target);
	if (rpc == NULL) {
		ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "mod_netconf: creating rpc request failed");
		return (EXIT_FAILURE);
	}

	retval = netconf_op(server, conns, session_key, rpc);
	nc_rpc_free (rpc);
	return (retval);
}

static int netconf_deleteconfig(server_rec* server, apr_hash_t* conns, const char* session_key, NC_DATASTORE target)
{
	return (netconf_onlytargetop(server, conns, session_key, target, nc_rpc_deleteconfig));
}

static int netconf_lock(server_rec* server, apr_hash_t* conns, const char* session_key, NC_DATASTORE target)
{
	return (netconf_onlytargetop(server, conns, session_key, target, nc_rpc_lock));
}

static int netconf_unlock(server_rec* server, apr_hash_t* conns, const char* session_key, NC_DATASTORE target)
{
	return (netconf_onlytargetop(server, conns, session_key, target, nc_rpc_unlock));
}

/**
 * @return REPLY_OK: 0, *data == NULL
 *         REPLY_DATA: 0, *data != NULL
 *         REPLY_ERROR: 1, *data == NULL
 */
static int netconf_generic(server_rec* server, apr_hash_t* conns, const char* session_key, const char* content, char** data)
{
	struct nc_session *session = NULL;
	nc_reply* reply;
	nc_rpc* rpc;
	int retval = EXIT_SUCCESS;
	NC_MSG_TYPE msgt;
	NC_REPLY_TYPE replyt;

	/* create requests */
	rpc = nc_rpc_generic(content);
	if (rpc == NULL) {
		ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "mod_netconf: creating rpc request failed");
		return (EXIT_FAILURE);
	}

	if (data != NULL) {
		*data = NULL;
	}

	/* get session where send the RPC */
	session = (struct nc_session *)apr_hash_get(conns, session_key, APR_HASH_KEY_STRING);
	if (session != NULL) {
		/* send the request and get the reply */
		msgt = nc_session_send_recv(session, rpc, &reply);
		nc_rpc_free (rpc);

		/* process the result of the operation */
		switch (msgt) {
		case NC_MSG_UNKNOWN:
			if (nc_session_get_status(session) != NC_SESSION_STATUS_WORKING) {
				ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "mod_netconf: receiving rpc-reply failed");
				netconf_close(server, conns, session_key);
				return (EXIT_FAILURE);
			}
			/* no break */
		case NC_MSG_NONE:
			/* there is error handled by callback */
			return (EXIT_FAILURE);
			break;
		case NC_MSG_REPLY:
			switch (replyt = nc_reply_get_type(reply)) {
			case NC_REPLY_DATA:
				if ((data != NULL) && (*data = nc_reply_get_data (reply)) == NULL) {
					ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "mod_netconf: no data from reply");
					nc_reply_free(reply);
					return (EXIT_FAILURE);
				}
				retval = EXIT_SUCCESS;
				break;
			case NC_REPLY_OK:
				retval = EXIT_SUCCESS;
				break;
			default:
				ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "mod_netconf: unexpected rpc-reply (%d)", replyt);
				retval = EXIT_FAILURE;
				break;
			}
			break;
		default:
			ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "mod_netconf: unexpected reply message received (%d)", msgt);
			retval = EXIT_FAILURE;
			break;
		}
		nc_reply_free(reply);

		return (retval);
	} else {
		ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "Unknown session to process.");
		return (EXIT_FAILURE);
	}
}

server_rec* clb_print_server;
void clb_print(NC_VERB_LEVEL level, const char* msg)
{
	switch (level) {
	case NC_VERB_ERROR:
		ap_log_error(APLOG_MARK, APLOG_ERR, 0, clb_print_server, msg);
		break;
	case NC_VERB_WARNING:
		ap_log_error(APLOG_MARK, APLOG_WARNING, 0, clb_print_server, msg);
		break;
	case NC_VERB_VERBOSE:
		ap_log_error(APLOG_MARK, APLOG_INFO, 0, clb_print_server, msg);
		break;
	case NC_VERB_DEBUG:
		ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, clb_print_server, msg);
		break;
	}
}

void * thread_routine (void * arg)
{
	void * retval = NULL;

	ssize_t buffer_len;
	struct pollfd fds;
	int status, buffer_size, ret;
	json_object *request, *reply, *json_obj, *capabilities;
	int operation;
	int i, chunk_len, len = 0;
	char* session_key, *data;
	const char *host, *port, *user, *pass;
	const char *msgtext, *cpbltstr;
	const char *target, *source, *filter, *config, *defop, *erropt, *sid;
	const char *identifier, *version, *format;
	struct nc_session *session = NULL;
	struct session_with_mutex * locked_session;
	struct nc_cpblts* cpblts = NULL;
	NC_DATASTORE ds_type_s, ds_type_t;
	NC_EDIT_DEFOP_TYPE defop_type = NC_EDIT_DEFOP_NOTSET;
	NC_EDIT_ERROPT_TYPE erropt_type = 0;

	apr_pool_t * pool = ((struct pass_to_thread*)arg)->pool;
	apr_hash_t *netconf_sessions_list = ((struct pass_to_thread*)arg)->netconf_sessions_list;
	server_rec * server = ((struct pass_to_thread*)arg)->server;
	int client = ((struct pass_to_thread*)arg)->client;

	char * buffer, chunk_len_str[12], *chunked_msg;
	char c;

	while (!isterminated) {
		fds.fd = client;
		fds.events = POLLIN;
		fds.revents = 0;

		status = poll(&fds, 1, 1000);

		if (status == 0 || (status == -1 && (errno == EAGAIN || (errno == EINTR && isterminated == 0)))) {
			/* poll was interrupted - check if the isterminated is set and if not, try poll again */
			//ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, server, "poll interrupted");
			continue;
		} else if (status < 0) {
			/* 0:  poll time outed
			 *     close socket and ignore this request from the client, it can try it again
			 * -1: poll failed
			 *     something wrong happend, close this socket and wait for another request
			 */
			//ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, server, "poll failed, status %d(%d: %s)", status, errno, strerror(errno));
			close(client);
			break;
		}
		/* status > 0 */

		/* check the status of the socket */

		/* if nothing to read and POLLHUP (EOF) or POLLERR set */
		if ((fds.revents & POLLHUP) || (fds.revents & POLLERR)) {
			/* close client's socket (it's probably already closed by client */
			//ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, server, "socket error (%d)", fds.revents);
			close(client);
			break;
		}

		/* read json in chunked framing */
		buffer_size = 0;
		buffer_len = 0;
		buffer = NULL;
		while (1) {
			/* read chunk length */
			if ((ret = recv (client, &c, 1, 0)) != 1 || c != '\n') {
				free (buffer);
				buffer = NULL;
				break;
			}
			if ((ret = recv (client, &c, 1, 0)) != 1 || c != '#') {
				free (buffer);
				buffer = NULL;
				break;
			}
			i=0;
			memset (chunk_len_str, 0, 12);
			while ((ret = recv (client, &c, 1, 0) == 1 && (isdigit(c) || c == '#'))) {
				if (i==0 && c == '#') {
					if (recv (client, &c, 1, 0) != 1 || c != '\n') {
						/* end but invalid */
						free (buffer);
						buffer = NULL;
					}
					/* end of message, double-loop break */
					goto msg_complete;
				}
				chunk_len_str[i++] = c;
			}
			if (c != '\n') {
				free (buffer);
				buffer = NULL;
				break;
			}
			if ((chunk_len = atoi (chunk_len_str)) == 0) {
				free (buffer);
				buffer = NULL;
				break;
			}
			buffer_size += chunk_len+1;
			buffer = realloc (buffer, sizeof(char)*buffer_size);
			if ((ret = recv (client, buffer+buffer_len, chunk_len, 0)) == -1 || ret != chunk_len) {
				free (buffer);
				buffer = NULL;
				break;
			}
			buffer_len += ret;
		}
msg_complete:

		if (buffer != NULL) {
			request = json_tokener_parse(buffer);
			operation = json_object_get_int(json_object_object_get(request, "type"));

			session_key = (char*) json_object_get_string(json_object_object_get(request, "session"));
			/* DO NOT FREE session_key HERE, IT IS PART OF REQUEST */
			if (operation != MSG_CONNECT && session_key == NULL) {
				reply =  json_object_new_object();
				json_object_object_add(reply, "type", json_object_new_int(REPLY_ERROR));
				json_object_object_add(reply, "error-message", json_object_new_string("Missing session specification."));
				msgtext = json_object_to_json_string(reply);
				send(client, msgtext, strlen(msgtext) + 1, 0);
				json_object_put(reply);
				/* there is some stupid client, so close the connection to give a chance to some other client */
				close(client);
				break;
			}

			/* get parameters */
			/* TODO NC_DATASTORE_URL */
			ds_type_t = -1;
			if ((target = json_object_get_string(json_object_object_get(request, "target"))) != NULL) {
				if (strcmp(target, "running") == 0) {
					ds_type_t = NC_DATASTORE_RUNNING;
				} else if (strcmp(target, "startup") == 0) {
					ds_type_t = NC_DATASTORE_STARTUP;
				} else if (strcmp(target, "candidate") == 0) {
					ds_type_t = NC_DATASTORE_CANDIDATE;
				}
			}
			ds_type_s = -1;
			if ((source = json_object_get_string(json_object_object_get(request, "source"))) != NULL) {
				if (strcmp(source, "running") == 0) {
					ds_type_s = NC_DATASTORE_RUNNING;
				} else if (strcmp(source, "startup") == 0) {
					ds_type_s = NC_DATASTORE_STARTUP;
				} else if (strcmp(source, "candidate") == 0) {
					ds_type_s = NC_DATASTORE_CANDIDATE;
				}
			}

			/* null global JSON error-reply */
			err_reply = NULL;

			/* prepare reply envelope */
			reply =  json_object_new_object();

			/* process required operation */
			switch (operation) {
			case MSG_CONNECT:
				ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, server, "Request: Connect");

				host = json_object_get_string(json_object_object_get(request, "host"));
				port = json_object_get_string(json_object_object_get(request, "port"));
				user = json_object_get_string(json_object_object_get(request, "user"));
				pass = json_object_get_string(json_object_object_get(request, "pass"));
				capabilities = json_object_object_get(request, "capabilities");
            if ((capabilities != NULL) && ((len = json_object_array_length(capabilities)) > 0)) {
                  cpblts = nc_cpblts_new (NULL);
                  for (i=0; i<len; i++) {
                     nc_cpblts_add (cpblts, json_object_get_string(json_object_array_get_idx(capabilities, i)));
                  }
            } else {
               ap_log_error (APLOG_MARK, APLOG_ERR, 0, server, "no capabilities specified");
            }
				ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, server, "host: %s, port: %s, user: %s", host, port, user);
				if ((host == NULL) || (user == NULL)) {
					ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, server, "Cannot connect - insufficient input.");
					session_key = NULL;
				} else {
					session_key = netconf_connect(server, pool, netconf_sessions_list, host, port, user, pass, cpblts);
               nc_cpblts_free (cpblts);
					ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, server, "hash: %s", session_key);
				}

				reply =  json_object_new_object();
				if (session_key == NULL) {
					/* negative reply */
					if (err_reply == NULL) {
						json_object_object_add(reply, "type", json_object_new_int(REPLY_ERROR));
						json_object_object_add(reply, "error-message", json_object_new_string("Connecting NETCONF server failed."));
						ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, server, "Connection failed.");
					} else {
						/* use filled err_reply from libnetconf's callback */
						json_object_put(reply);
						reply = err_reply;
						ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, server, "Connect - error from libnetconf's callback.");
					}
				} else {
					/* positive reply */
					json_object_object_add(reply, "type", json_object_new_int(REPLY_OK));
					json_object_object_add(reply, "session", json_object_new_string(session_key));

					free(session_key);
				}

				break;
			case MSG_GET:
				ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, server, "Request: get (session %s)", session_key);

				filter = json_object_get_string(json_object_object_get(request, "filter"));

				//ap_log_error (APLOG_MARK, APLOG_ERR, 0, server, "get filter: %p", filter);

				if ((data = netconf_get(server, netconf_sessions_list, session_key, filter)) == NULL) {
					if (err_reply == NULL) {
						json_object_object_add(reply, "type", json_object_new_int(REPLY_ERROR));
						json_object_object_add(reply, "error-message", json_object_new_string("get failed."));
					} else {
						/* use filled err_reply from libnetconf's callback */
						json_object_put(reply);
						reply = err_reply;
					}
				} else {
					json_object_object_add(reply, "type", json_object_new_int(REPLY_DATA));
					json_object_object_add(reply, "data", json_object_new_string(data));
				}
				break;
			case MSG_GETCONFIG:
				ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, server, "Request: get-config (session %s)", session_key);

				filter = json_object_get_string(json_object_object_get(request, "filter"));

				if (ds_type_s == -1) {
					json_object_object_add(reply, "type", json_object_new_int(REPLY_ERROR));
					json_object_object_add(reply, "error-message", json_object_new_string("Invalid source repository type requested."));
					break;
				}

				if ((data = netconf_getconfig(server, netconf_sessions_list, session_key, ds_type_s, filter)) == NULL) {
					if (err_reply == NULL) {
						json_object_object_add(reply, "type", json_object_new_int(REPLY_ERROR));
						json_object_object_add(reply, "error-message", json_object_new_string("get-config failed."));
					} else {
						/* use filled err_reply from libnetconf's callback */
						json_object_put(reply);
						reply = err_reply;
					}
				} else {
					json_object_object_add(reply, "type", json_object_new_int(REPLY_DATA));
					json_object_object_add(reply, "data", json_object_new_string(data));
				}
				break;
			case MSG_GETSCHEMA:
				ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, server, "Request: get-schema (session %s)", session_key);
				identifier = json_object_get_string(json_object_object_get(request, "identifier"));
				if (identifier == NULL) {
					json_object_object_add(reply, "type", json_object_new_int(REPLY_ERROR));
					json_object_object_add(reply, "error-message", json_object_new_string("No identifier for get-schema supplied."));
					break;
				}
				version = json_object_get_string(json_object_object_get(request, "version"));
				format = json_object_get_string(json_object_object_get(request, "format"));

				ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, server, "get-schema(version: %s, format: %s)", version, format);
				if ((data = netconf_getschema(server, netconf_sessions_list, session_key, identifier, version, format)) == NULL) {
					if (err_reply == NULL) {
						json_object_object_add(reply, "type", json_object_new_int(REPLY_ERROR));
						json_object_object_add(reply, "error-message", json_object_new_string("get-config failed."));
					} else {
						/* use filled err_reply from libnetconf's callback */
						json_object_put(reply);
						reply = err_reply;
					}
				} else {
					json_object_object_add(reply, "type", json_object_new_int(REPLY_DATA));
					json_object_object_add(reply, "data", json_object_new_string(data));
				}
				break;
			case MSG_EDITCONFIG:
				ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, server, "Request: edit-config (session %s)", session_key);

				defop = json_object_get_string(json_object_object_get(request, "default-operation"));
				if (defop != NULL) {
					if (strcmp(defop, "merge") == 0) {
						defop_type = NC_EDIT_DEFOP_MERGE;
					} else if (strcmp(defop, "replace") == 0) {
						defop_type = NC_EDIT_DEFOP_REPLACE;
					} else if (strcmp(defop, "none") == 0) {
						defop_type = NC_EDIT_DEFOP_NONE;
					} else {
						json_object_object_add(reply, "type", json_object_new_int(REPLY_ERROR));
						json_object_object_add(reply, "error-message", json_object_new_string("Invalid default-operation parameter."));
						break;
					}
				} else {
					defop_type = NC_EDIT_DEFOP_NOTSET;
				}

				erropt = json_object_get_string(json_object_object_get(request, "error-option"));
				if (erropt != NULL) {
					if (strcmp(erropt, "continue-on-error") == 0) {
						erropt_type = NC_EDIT_ERROPT_CONT;
					} else if (strcmp(erropt, "stop-on-error") == 0) {
						erropt_type = NC_EDIT_ERROPT_STOP;
					} else if (strcmp(erropt, "rollback-on-error") == 0) {
						erropt_type = NC_EDIT_ERROPT_ROLLBACK;
					} else {
						json_object_object_add(reply, "type", json_object_new_int(REPLY_ERROR));
						json_object_object_add(reply, "error-message", json_object_new_string("Invalid error-option parameter."));
						break;
					}
				} else {
					erropt_type = 0;
				}

				if (ds_type_t == -1) {
					json_object_object_add(reply, "type", json_object_new_int(REPLY_ERROR));
					json_object_object_add(reply, "error-message", json_object_new_string("Invalid target repository type requested."));
					break;
				}

				config = json_object_get_string(json_object_object_get(request, "config"));
				if (config == NULL) {
					json_object_object_add(reply, "type", json_object_new_int(REPLY_ERROR));
					json_object_object_add(reply, "error-message", json_object_new_string("Invalid config data parameter."));
					break;
				}

				/* TODO url capability see netconf_editconfig */
				/* TODO TESTSET - :validate:1.1 capability? http://tools.ietf.org/html/rfc6241#section-7.2 */
				if (netconf_editconfig(server, netconf_sessions_list, session_key, ds_type_t, defop_type, erropt_type, NC_EDIT_TESTOPT_NOTSET, config) != EXIT_SUCCESS) {
					if (err_reply == NULL) {
						json_object_object_add(reply, "type", json_object_new_int(REPLY_ERROR));
						json_object_object_add(reply, "error-message", json_object_new_string("edit-config failed."));
					} else {
						/* use filled err_reply from libnetconf's callback */
						json_object_put(reply);
						reply = err_reply;
					}
				} else {
					json_object_object_add(reply, "type", json_object_new_int(REPLY_OK));
				}
				break;
			case MSG_COPYCONFIG:
				ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, server, "Request: copy-config (session %s)", session_key);
				config = NULL;

				if (source == NULL) {
					/* no explicit source specified -> use config data */
					ds_type_s = NC_DATASTORE_CONFIG;
					config = json_object_get_string(json_object_object_get(request, "config"));
				} else if (ds_type_s == -1) {
					/* source datastore specified, but it is invalid */
					json_object_object_add(reply, "type", json_object_new_int(REPLY_ERROR));
					json_object_object_add(reply, "error-message", json_object_new_string("Invalid source repository type requested."));
					break;
				}

				if (ds_type_t == -1) {
					/* invalid target datastore specified */
					json_object_object_add(reply, "type", json_object_new_int(REPLY_ERROR));
					json_object_object_add(reply, "error-message", json_object_new_string("Invalid target repository type requested."));
					break;
				}

				if (source == NULL && config == NULL) {
					json_object_object_add(reply, "type", json_object_new_int(REPLY_ERROR));
					json_object_object_add(reply, "error-message", json_object_new_string("invalid input parameters - one of source and config is required."));
				} else {
					if (netconf_copyconfig(server, netconf_sessions_list, session_key, ds_type_s, ds_type_t, config, "") != EXIT_SUCCESS) {
						if (err_reply == NULL) {
							json_object_object_add(reply, "type", json_object_new_int(REPLY_ERROR));
							json_object_object_add(reply, "error-message", json_object_new_string("copy-config failed."));
						} else {
							/* use filled err_reply from libnetconf's callback */
							json_object_put(reply);
							reply = err_reply;
						}
					} else {
						json_object_object_add(reply, "type", json_object_new_int(REPLY_OK));
					}
				}
				break;
			case MSG_DELETECONFIG:
				ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, server, "Request: delete-config (session %s)", session_key);
				/* no break - unifying code */
			case MSG_LOCK:
				if (operation == MSG_LOCK) {
					ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, server, "Request: lock (session %s)", session_key);
				}
				/* no break - unifying code */
			case MSG_UNLOCK:
				if (operation == MSG_UNLOCK) {
					ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, server, "Request: unlock (session %s)", session_key);
				}

				if (ds_type_t == -1) {
					json_object_object_add(reply, "type", json_object_new_int(REPLY_ERROR));
					json_object_object_add(reply, "error-message", json_object_new_string("Invalid target repository type requested."));
					break;
				}

				switch(operation) {
				case MSG_DELETECONFIG:
					status = netconf_deleteconfig(server, netconf_sessions_list, session_key, ds_type_t);
					break;
				case MSG_LOCK:
					status = netconf_lock(server, netconf_sessions_list, session_key, ds_type_t);
					break;
				case MSG_UNLOCK:
					status = netconf_unlock(server, netconf_sessions_list, session_key, ds_type_t);
					break;
				default:
					status = -1;
					break;
				}

				if (status != EXIT_SUCCESS) {
					if (err_reply == NULL) {
						json_object_object_add(reply, "type", json_object_new_int(REPLY_ERROR));
						json_object_object_add(reply, "error-message", json_object_new_string("operation failed."));
					} else {
						/* use filled err_reply from libnetconf's callback */
						json_object_put(reply);
						reply = err_reply;
					}
				} else {
					json_object_object_add(reply, "type", json_object_new_int(REPLY_OK));
				}
				break;
			case MSG_KILL:
				ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, server, "Request: kill-session, session %s", session_key);

				sid = json_object_get_string(json_object_object_get(request, "session-id"));

				if (sid == NULL) {
					json_object_object_add(reply, "type", json_object_new_int(REPLY_ERROR));
					json_object_object_add(reply, "error-message", json_object_new_string("Missing session-id parameter."));
					break;
				}

				if (netconf_killsession(server, netconf_sessions_list, session_key, sid) != EXIT_SUCCESS) {
					if (err_reply == NULL) {
						json_object_object_add(reply, "type", json_object_new_int(REPLY_ERROR));
						json_object_object_add(reply, "error-message", json_object_new_string("kill-session failed."));
					} else {
						/* use filled err_reply from libnetconf's callback */
						json_object_put(reply);
						reply = err_reply;
					}
				} else {
					json_object_object_add(reply, "type", json_object_new_int(REPLY_OK));
				}
				break;
			case MSG_DISCONNECT:
				ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, server, "Request: Disconnect session %s", session_key);

				if (netconf_close(server, netconf_sessions_list, session_key) != EXIT_SUCCESS) {
					if (err_reply == NULL) {
						json_object_object_add(reply, "type", json_object_new_int(REPLY_ERROR));
						json_object_object_add(reply, "error-message", json_object_new_string("Invalid session identifier."));
					} else {
						/* use filled err_reply from libnetconf's callback */
						json_object_put(reply);
						reply = err_reply;
					}
				} else {
					json_object_object_add(reply, "type", json_object_new_int(REPLY_OK));
				}
				break;
			case MSG_INFO:
				ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, server, "Request: get info about session %s", session_key);

				locked_session = (struct session_with_mutex *)apr_hash_get(netconf_sessions_list, session_key, APR_HASH_KEY_STRING);
				if (locked_session != NULL) {
					session = locked_session->session;
				} else {
					session = NULL;
				}
				if (session != NULL) {
					json_object_object_add(reply, "sid", json_object_new_string(nc_session_get_id(session)));
					json_object_object_add(reply, "version", json_object_new_string((nc_session_get_version(session) == 0)?"1.0":"1.1"));
					json_object_object_add(reply, "host", json_object_new_string(nc_session_get_host(session)));
					json_object_object_add(reply, "port", json_object_new_string(nc_session_get_port(session)));
					json_object_object_add(reply, "user", json_object_new_string(nc_session_get_user(session)));
					cpblts = nc_session_get_cpblts (session);
					if (cpblts != NULL) {
						json_obj = json_object_new_array();
						nc_cpblts_iter_start (cpblts);
						while ((cpbltstr = nc_cpblts_iter_next (cpblts)) != NULL) {
							json_object_array_add(json_obj, json_object_new_string(cpbltstr));
						}
						json_object_object_add(reply, "capabilities", json_obj);
					}
				} else {
					json_object_object_add(reply, "type", json_object_new_int(REPLY_ERROR));
					json_object_object_add(reply, "error-message", json_object_new_string("Invalid session identifier."));
				}

				break;
			case MSG_GENERIC:
				ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, server, "Request: generic request for session %s", session_key);

				config = json_object_get_string(json_object_object_get(request, "content"));

				if (config == NULL) {
					json_object_object_add(reply, "type", json_object_new_int(REPLY_ERROR));
					json_object_object_add(reply, "error-message", json_object_new_string("Missing content parameter."));
					break;
				}

				if (netconf_generic(server, netconf_sessions_list, session_key, config, &data) != EXIT_SUCCESS) {
					if (err_reply == NULL) {
						json_object_object_add(reply, "type", json_object_new_int(REPLY_ERROR));
						json_object_object_add(reply, "error-message", json_object_new_string("kill-session failed."));
					} else {
						/* use filled err_reply from libnetconf's callback */
						json_object_put(reply);
						reply = err_reply;
					}
				} else {
					if (data == NULL) {
						json_object_object_add(reply, "type", json_object_new_int(REPLY_OK));
					} else {
						json_object_object_add(reply, "type", json_object_new_int(REPLY_DATA));
						json_object_object_add(reply, "data", json_object_new_string(data));
					}
				}
				break;
			default:
				ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "Unknown mod_netconf operation requested (%d)", operation);
				reply =  json_object_new_object();
				json_object_object_add(reply, "type", json_object_new_int(REPLY_ERROR));
				json_object_object_add(reply, "error-message", json_object_new_string("Operation not supported."));
				break;
			}
			json_object_put(request);

			/* send reply to caller */
			if (reply != NULL) {
				msgtext = json_object_to_json_string(reply);
				if (asprintf (&chunked_msg, "\n#%d\n%s\n##\n", (int)strlen(msgtext), msgtext) == -1) {
					free (buffer);
					break;
				}
				send(client, chunked_msg, strlen(chunked_msg) + 1, 0);
				json_object_put(reply);
				free (chunked_msg);
				free (buffer);
			} else {
				break;
			}
		}
	}

	free (arg);

	return retval;
}

/*
 * This is actually implementation of NETCONF client
 * - requests are received from UNIX socket in the predefined format
 * - results are replied through the same way
 * - the daemon run as a separate process, but it is started and stopped
 *   automatically by Apache.
 *
 */
static void forked_proc(apr_pool_t * pool, server_rec * server)
{
	struct sockaddr_un local, remote;
	int lsock, client, ret, i, pthread_count = 0;
	socklen_t len;
	mod_netconf_cfg *cfg;
	apr_hash_t *netconf_sessions_list;
	struct pass_to_thread * arg;
	pthread_t * ptids = calloc (1,sizeof(pthread_t));
	struct timespec maxtime;
	pthread_rwlockattr_t lock_attrs;

	/* wait at most 5 secons for every thread to terminate */
	maxtime.tv_sec = 5;
	maxtime.tv_nsec = 0;

	/* change uid and gid of process for security reasons */
	unixd_setup_child();

	cfg = ap_get_module_config(server->module_config, &netconf_module);
	if (cfg == NULL) {
		ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "Getting mod_netconf configuration failed");
		return;
	}

	/* create listening UNIX socket to accept incoming connections */
	if ((lsock = socket(PF_UNIX, SOCK_STREAM, 0)) == -1) {
		ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "Creating socket failed (%s)", strerror(errno));
		return;
	}

	local.sun_family = AF_UNIX;
	strncpy(local.sun_path, cfg->sockname, sizeof(local.sun_path));
	unlink(local.sun_path);
	len = offsetof(struct sockaddr_un, sun_path) + strlen(local.sun_path);

	if (bind(lsock, (struct sockaddr *) &local, len) == -1) {
		if (errno == EADDRINUSE) {
			ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, server, "mod_netconf socket address already in use");
			close(lsock);
			exit(0);
		}
		ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "Binding socket failed (%s)", strerror(errno));
		close(lsock);
		return;
	}

	if (listen(lsock, MAX_SOCKET_CL) == -1) {
		ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "Setting up listen socket failed (%s)", strerror(errno));
		close(lsock);
		return;
	}

	/* prepare internal lists */
	netconf_sessions_list = apr_hash_make(pool);

	/* setup libnetconf's callbacks */
	nc_verbosity(NC_VERB_DEBUG);
	clb_print_server = server;
	nc_callback_print(clb_print);
	nc_callback_ssh_host_authenticity_check(netconf_callback_ssh_hostkey_check);
	nc_callback_sshauth_interactive(netconf_callback_sshauth_interactive);
	nc_callback_sshauth_password(netconf_callback_sshauth_password);
	nc_callback_error_reply(netconf_callback_error_process);

	/* disable publickey authentication */
	nc_ssh_pref(NC_SSH_AUTH_PUBLIC_KEYS, -1);

	/* create mutex protecting session list */
	pthread_rwlockattr_init(&lock_attrs);
	/* rwlock is shared only with threads in this process */
	pthread_rwlockattr_setpshared(&lock_attrs, PTHREAD_PROCESS_PRIVATE);
	/* create rw lock */
	if (pthread_rwlock_init(&session_lock, &lock_attrs) != 0) {
		ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "Initialization of mutex failed: %d (%s)", errno, strerror(errno));
		close (lsock);
		return;
	}

	while (isterminated == 0) {
		ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, server, "waiting for another client's request");

		/* open incoming connection if any */
		len = sizeof(remote);
		client = accept(lsock, (struct sockaddr *) &remote, &len);
		if (client == -1 && (errno == EAGAIN || errno == EWOULDBLOCK)) {
			apr_sleep(SLEEP_TIME);
			continue;
		} else if (client == -1 && (errno == EINTR)) {
			continue;
		} else if (client == -1) {
			ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "Accepting mod_netconf client connection failed (%s)", strerror(errno));
			continue;
		}

		/* set client's socket as non-blocking */
		//fcntl(client, F_SETFL, fcntl(client, F_GETFL, 0) | O_NONBLOCK);

		arg = malloc (sizeof(struct pass_to_thread));
		arg->client = client;
		arg->pool = pool;
		arg->server = server;
		arg->netconf_sessions_list = netconf_sessions_list;

		/* start new thread. It will serve this particular request and then terminate */
		if ((ret = pthread_create (&ptids[pthread_count], NULL, thread_routine, (void*)arg)) != 0) {
			ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "Creating POSIX thread failed: %d\n", ret);
		} else {
			ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "Thread %lu created", ptids[pthread_count]);
			pthread_count++;
			ptids = realloc (ptids, sizeof(pthread_t)*(pthread_count+1));
			ptids[pthread_count] = 0;
		}

		/* check if some thread already terminated, free some resources by joining it */
		for (i=0; i<pthread_count; i++) {
			if (pthread_tryjoin_np (ptids[i], (void**)&arg) == 0) {
				ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "Thread %lu joined with retval %p", ptids[i], arg);
				pthread_count--;
				if (pthread_count > 0) {
					/* place last Thread ID on the place of joined one */
					ptids[i] = ptids[pthread_count];
				}
			}
		}
		ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "Running %d threads", pthread_count);
	}

	/* join all threads */
	for (i=0; i<pthread_count; i++) {
		pthread_timedjoin_np (ptids[i], (void**)&arg, &maxtime);
	}
	free (ptids);

	close(lsock);

	/* destroy rwlock */
	pthread_rwlock_destroy(&session_lock);
	pthread_rwlockattr_destroy(&lock_attrs);

	ap_log_error(APLOG_MARK, APLOG_ERR, 0, server, "Exiting from the mod_netconf daemon");

	exit(APR_SUCCESS);
}

static void *mod_netconf_create_conf(apr_pool_t * pool, server_rec * s)
{
	ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, "Init netconf module config");

	mod_netconf_cfg *config = apr_pcalloc(pool, sizeof(mod_netconf_cfg));
	apr_pool_create(&config->pool, pool);
	config->forkproc = NULL;
	config->sockname = SOCKET_FILENAME;

	return (void *)config;
}

static int mod_netconf_master_init(apr_pool_t * pconf, apr_pool_t * ptemp,
		  apr_pool_t * plog, server_rec * s)
{
	mod_netconf_cfg *config;
	apr_status_t res;

	/* These two help ensure that we only init once. */
	void *data = NULL;
	const char *userdata_key = "netconf_ipc_init";

	/*
	 * The following checks if this routine has been called before.
	 * This is necessary because the parent process gets initialized
	 * a couple of times as the server starts up.
	 */
	apr_pool_userdata_get(&data, userdata_key, s->process->pool);
	if (!data) {
		apr_pool_userdata_set((const void *)1, userdata_key, apr_pool_cleanup_null, s->process->pool);
		return (OK);
	}

	ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, "creating mod_netconf daemon");
	config = ap_get_module_config(s->module_config, &netconf_module);

	if (config && config->forkproc == NULL) {
		config->forkproc = apr_pcalloc(config->pool, sizeof(apr_proc_t));
		res = apr_proc_fork(config->forkproc, config->pool);
		switch (res) {
		case APR_INCHILD:
			/* set signal handler */
			apr_signal_init(config->pool);
			apr_signal(SIGTERM, signal_handler);

			/* log start of the separated NETCONF communication process */
			ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, s, "mod_netconf daemon started (PID %d)", getpid());

			/* start main loop providing NETCONF communication */
			forked_proc(config->pool, s);

			/* I never should be here, wtf?!? */
			ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, "mod_netconf daemon unexpectedly stopped");
			exit(APR_EGENERAL);
			break;
		case APR_INPARENT:
			/* register child to be killed (SIGTERM) when the module config's pool dies */
			apr_pool_note_subprocess(config->pool, config->forkproc, APR_KILL_AFTER_TIMEOUT);
			break;
		default:
			ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, "apr_proc_fork() failed");
			break;
		}
	} else {
		ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, "mod_netconf misses configuration structure");
	}

	return OK;
}

/**
 * Register module hooks
 */
static void mod_netconf_register_hooks(apr_pool_t * p)
{
	ap_hook_post_config(mod_netconf_master_init, NULL, NULL, APR_HOOK_LAST);
}

static const char* cfg_set_socket_path(cmd_parms* cmd, void* cfg, const char* arg)
{
	((mod_netconf_cfg*)cfg)->sockname = apr_pstrdup(cmd->pool, arg);
	return NULL;
}

static const command_rec netconf_cmds[] = {
		AP_INIT_TAKE1("NetconfSocket", cfg_set_socket_path, NULL, OR_ALL, "UNIX socket path for mod_netconf communication."),
		{NULL}
};

/* Dispatch list for API hooks */
module AP_MODULE_DECLARE_DATA netconf_module = {
	STANDARD20_MODULE_STUFF,
	NULL,			/* create per-dir    config structures */
	NULL,			/* merge  per-dir    config structures */
	mod_netconf_create_conf,	/* create per-server config structures */
	NULL,			/* merge  per-server config structures */
	netconf_cmds,			/* table of config file commands       */
	mod_netconf_register_hooks	/* register hooks                      */
};