res_calendar_exchange.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2008 - 2009, Digium, Inc.
 *
 * Terry Wilson <[email protected]>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 * \brief Resource for handling MS Exchange calendars
 */

/*** MODULEINFO
 <depend>res_calendar</depend>
 <depend>neon</depend>
 <depend>ical</depend>
 <depend>iksemel</depend>
 <support_level>extended</support_level>
***/

#include "asterisk.h"

#include <libical/ical.h>
#include <ne_session.h>
#include <ne_uri.h>
#include <ne_request.h>
#include <ne_auth.h>
#include <ne_redirect.h>
#include <iksemel.h>

#include "asterisk/module.h"
#include "asterisk/channel.h"
#include "asterisk/calendar.h"
#include "asterisk/lock.h"
#include "asterisk/config.h"
#include "asterisk/astobj2.h"
#include "asterisk/uuid.h"

static void *exchangecal_load_calendar(void *data);
static void *unref_exchangecal(void *obj);
static int exchangecal_write_event(struct ast_calendar_event *event);

static struct ast_calendar_tech exchangecal_tech = {
 .type = "exchange",
 .description = "MS Exchange calendars",
 .module = AST_MODULE,
 .load_calendar = exchangecal_load_calendar,
 .unref_calendar = unref_exchangecal,
 .write_event = exchangecal_write_event,
};

struct exchangecal_pvt {
 AST_DECLARE_STRING_FIELDS(
 AST_STRING_FIELD(url);
 AST_STRING_FIELD(user);
 AST_STRING_FIELD(secret);
 );
 struct ast_calendar *owner;
 ne_uri uri;
 ne_session *session;
 struct ao2_container *events;
};

struct xmlstate {
 char tag[80];
 int in_response;
 int in_propstat;
 int in_prop;
 void *ptr;
 struct exchangecal_pvt *pvt;
};

static int parse_tag(void *data, char *name, char **atts, int type)
{
 struct xmlstate *state = data;
 char *tmp;

 if ((tmp = strchr(name, ':'))) {
 tmp++;
 } else {
 return IKS_HOOK;
 }

 ast_copy_string(state->tag, tmp, sizeof(state->tag));

 switch (type) {
 case IKS_OPEN:
 if (!strcasecmp(state->tag, "response")) {
 struct ast_calendar_event *event;

 state->in_response = 1;
 if (!(event = ast_calendar_event_alloc(state->pvt->owner))) {
 return IKS_NOMEM;
 }
 state->ptr = event;
 } else if (!strcasecmp(state->tag, "propstat")) {
 state->in_propstat = 1;
 } else if (!strcasecmp(state->tag, "prop")) {
 state->in_prop = 1;
 }
 break;

 case IKS_CLOSE:
 if (!strcasecmp(state->tag, "response")) {
 struct ao2_container *events = state->pvt->events;
 struct ast_calendar_event *event = state->ptr;

 state->in_response = 0;
 if (ast_strlen_zero(event->uid)) {
 ast_log(LOG_ERROR, "This event has no UID, something has gone wrong\n");
 event = ast_calendar_unref_event(event);
 return IKS_HOOK;
 }
 ao2_link(events, event);
 event = ast_calendar_unref_event(event);
 } else if (!strcasecmp(state->tag, "propstat")) {
 state->in_propstat = 0;
 } else if (!strcasecmp(state->tag, "prop")) {
 state->in_prop = 0;
 }
 break;

 default:
 return IKS_OK;
 }

 return IKS_OK;
}

static time_t mstime_to_time_t(char *mstime)
{
 char *read, *write;
 icaltimetype tt;
 for (read = write = mstime; *read; read++) {
 if (*read == '.') {
 *write++ = 'Z';
 *write = '\0';
 break;
 }
 if (*read == '-' || *read == ':')
 continue;
 *write = *read;
 write++;
 }

 tt = icaltime_from_string(mstime);
 return icaltime_as_timet(tt);
}

static enum ast_calendar_busy_state msbusy_to_bs(const char *msbusy)
{
 if (!strcasecmp(msbusy, "FREE")) {
 return AST_CALENDAR_BS_FREE;
 } else if (!strcasecmp(msbusy, "TENTATIVE")) {
 return AST_CALENDAR_BS_BUSY_TENTATIVE;
 } else {
 return AST_CALENDAR_BS_BUSY;
 }
}

static int parse_cdata(void *data, char *value, size_t len)
{
 char *str;
 struct xmlstate *state = data;
 struct ast_calendar_event *event = state->ptr;


 str = ast_skip_blanks(value);

 if (str == value + len)
 return IKS_OK;

 if (!(str = ast_calloc(1, len + 1))) {
 return IKS_NOMEM;
 }
 memcpy(str, value, len);
 if (!(state->in_response && state->in_propstat && state->in_prop)) {
 ast_free(str);
 return IKS_OK;
 }
 /* We use ast_string_field_build here because libiksemel is parsing CDATA with &lt; as
 * new elements which is a bit odd and shouldn't happen */
 if (!strcasecmp(state->tag, "subject")) {
 ast_string_field_build(event, summary, "%s%s", event->summary, str);
 } else if (!strcasecmp(state->tag, "location")) {
 ast_string_field_build(event, location, "%s%s", event->location, str);
 } else if (!strcasecmp(state->tag, "uid")) {
 ast_string_field_build(event, uid, "%s%s", event->location, str);
 } else if (!strcasecmp(state->tag, "organizer")) {
 ast_string_field_build(event, organizer, "%s%s", event->organizer, str);
 } else if (!strcasecmp(state->tag, "textdescription")) {
 ast_string_field_build(event, description, "%s%s", event->description, str);
 } else if (!strcasecmp(state->tag, "dtstart")) {
 event->start = mstime_to_time_t(str);
 } else if (!strcasecmp(state->tag, "dtend")) {
 event->end = mstime_to_time_t(str);
 } else if (!strcasecmp(state->tag, "busystatus")) {
 event->busy_state = msbusy_to_bs(str);
 } else if (!strcasecmp(state->tag, "reminderoffset")) {
 /*XXX Currently we rely on event->start being set first which means we rely on the response order
 * which technically should be fine since the query returns in the order we ask for, but ... */
 event->alarm = event->start - atoi(str);
 }

 ast_free(str);
 return IKS_OK;
}

static void exchangecal_destructor(void *obj)
{
 struct exchangecal_pvt *pvt = obj;

 ast_debug(1, "Destroying pvt for Exchange calendar %s\n", pvt->owner->name);
 if (pvt->session) {
 ne_session_destroy(pvt->session);
 }
 ne_uri_free(&pvt->uri);
 ast_string_field_free_memory(pvt);

 ao2_callback(pvt->events, OBJ_UNLINK | OBJ_NODATA | OBJ_MULTIPLE, NULL, NULL);

 ao2_ref(pvt->events, -1);
}

static void *unref_exchangecal(void *obj)
{
 struct exchangecal_pvt *pvt = obj;

 ao2_ref(pvt, -1);
 return NULL;
}

/* It is very important to use the return value of this function as a realloc could occur */
static struct ast_str *generate_exchange_uuid(struct ast_str *uid)
{
 char buffer[AST_UUID_STR_LEN];

 ast_uuid_generate_str(buffer, sizeof(buffer));
 ast_str_set(&uid, 0, "%s", buffer);
 return uid;
}

static int is_valid_uuid(struct ast_str *uid)
{
 struct ast_uuid *uuid = ast_str_to_uuid(ast_str_buffer(uid));

 if (uuid) {
 ast_free(uuid);
 return 1;
 }

 return 0;
}

static struct ast_str *xml_encode_str(struct ast_str *dst, const char *src)
{
 const char *tmp;
 char buf[7];

 for (tmp = src; *tmp; tmp++) {
 switch (*tmp) {
 case '\"':
 strcpy(buf, "&quot;");
 break;

 case '\'':
 strcpy(buf, "&apos;");
 break;

 case '&':
 strcpy(buf, "&amp;");
 break;

 case '<':
 strcpy(buf, "&lt;");
 break;

 case '>':
 strcpy(buf, "&gt;");
 break;

 default:
 sprintf(buf, "%c", *tmp);
 }

 ast_str_append(&dst, 0, "%s", buf);
 }

 return dst;
}

static struct ast_str *epoch_to_exchange_time(struct ast_str *dst, time_t epoch)
{
 icaltimezone *utc = icaltimezone_get_utc_timezone();
 icaltimetype tt = icaltime_from_timet_with_zone(epoch, 0, utc);
 char tmp[30];
 int i;

 ast_copy_string(tmp, icaltime_as_ical_string(tt), sizeof(tmp));
 for (i = 0; tmp[i]; i++) {
 ast_str_append(&dst, 0, "%c", tmp[i]);
 if (i == 3 || i == 5)
 ast_str_append(&dst, 0, "%c", '-');
 if (i == 10 || i == 12)
 ast_str_append(&dst, 0, "%c", ':');
 if (i == 14)
 ast_str_append(&dst, 0, "%s", ".000");
 }

 return dst;
}

static struct ast_str *bs_to_exchange_bs(struct ast_str *dst, enum ast_calendar_busy_state bs)
{
 switch (bs) {
 case AST_CALENDAR_BS_BUSY:
 ast_str_set(&dst, 0, "%s", "BUSY");
 break;

 case AST_CALENDAR_BS_BUSY_TENTATIVE:
 ast_str_set(&dst, 0, "%s", "TENTATIVE");
 break;

 default:
 ast_str_set(&dst, 0, "%s", "FREE");
 }

 return dst;
}

static int fetch_response_reader(void *data, const char *block, size_t len)
{
 struct ast_str **response = data;
 unsigned char *tmp;

 if (!(tmp = ast_malloc(len + 1))) {
 return -1;
 }
 memcpy(tmp, block, len);
 tmp[len] = '\0';
 ast_str_append(response, 0, "%s", tmp);
 ast_free(tmp);

 return 0;
}

static int auth_credentials(void *userdata, const char *realm, int attempts, char *username, char *secret)
{
 struct exchangecal_pvt *pvt = userdata;

 if (attempts > 1) {
 ast_log(LOG_WARNING, "Invalid username or password for Exchange calendar '%s'\n", pvt->owner->name);
 return -1;
 }

 ne_strnzcpy(username, pvt->user, NE_ABUFSIZ);
 ne_strnzcpy(secret, pvt->secret, NE_ABUFSIZ);

 return 0;
}

static struct ast_str *exchangecal_request(struct exchangecal_pvt *pvt, const char *method, struct ast_str *req_body, struct ast_str *subdir)
{
 struct ast_str *response;
 ne_request *req;
 int ret;
 char buf[1000];

 if (!pvt) {
 ast_log(LOG_ERROR, "There is no private!\n");
 return NULL;
 }

 if (!(response = ast_str_create(512))) {
 ast_log(LOG_ERROR, "Could not allocate memory for response.\n");
 return NULL;
 }

 snprintf(buf, sizeof(buf), "%s%s", pvt->uri.path, subdir ? ast_str_buffer(subdir) : "");

 req = ne_request_create(pvt->session, method, buf);
 ne_add_response_body_reader(req, ne_accept_2xx, fetch_response_reader, &response);
 ne_set_request_body_buffer(req, ast_str_buffer(req_body), ast_str_strlen(req_body));
 ne_add_request_header(req, "Content-type", "text/xml");

 ret = ne_request_dispatch(req);
 ne_request_destroy(req);

 if (ret != NE_OK || !ast_str_strlen(response)) {
 ast_log(LOG_WARNING, "Unknown response to CalDAV calendar %s, request %s to %s: %s\n", pvt->owner->name, method, pvt->url, ne_get_error(pvt->session));
 ast_free(response);
 return NULL;
 }

 return response;
}

static int exchangecal_write_event(struct ast_calendar_event *event)
{
 struct ast_str *body = NULL;
 struct ast_str *response = NULL;
 struct ast_str *subdir = NULL;
 struct ast_str *uid = NULL;
 struct ast_str *summary = NULL;
 struct ast_str *description = NULL;
 struct ast_str *organizer = NULL;
 struct ast_str *location = NULL;
 struct ast_str *start = NULL;
 struct ast_str *end = NULL;
 struct ast_str *busystate = NULL;
 int ret = -1;

 if (!event) {
 ast_log(LOG_WARNING, "No event passed!\n");
 return -1;
 }

 if (!(event->start && event->end)) {
 ast_log(LOG_WARNING, "The event must contain a start and an end\n");
 return -1;
 }
 if (!(body = ast_str_create(512)) ||
 !(subdir = ast_str_create(32))) {
 ast_log(LOG_ERROR, "Could not allocate memory for request!\n");
 goto write_cleanup;
 }

 if (!(uid = ast_str_create(AST_UUID_STR_LEN)) ||
 !(summary = ast_str_create(32)) ||
 !(description = ast_str_create(32)) ||
 !(organizer = ast_str_create(32)) ||
 !(location = ast_str_create(32)) ||
 !(start = ast_str_create(32)) ||
 !(end = ast_str_create(32)) ||
 !(busystate = ast_str_create(32))) {
 ast_log(LOG_ERROR, "Unable to allocate memory for request values\n");
 goto write_cleanup;
 }

 if (ast_strlen_zero(event->uid)) {
 uid = generate_exchange_uuid(uid);
 } else {
 ast_str_set(&uid, AST_UUID_STR_LEN, "%s", event->uid);
 }

 if (!is_valid_uuid(uid)) {
 ast_log(LOG_WARNING, "An invalid uid was provided, you may leave this field blank to have one generated for you\n");
 goto write_cleanup;
 }

 summary = xml_encode_str(summary, event->summary);
 description = xml_encode_str(description, event->description);
 organizer = xml_encode_str(organizer, event->organizer);
 location = xml_encode_str(location, event->location);
 start = epoch_to_exchange_time(start, event->start);
 end = epoch_to_exchange_time(end, event->end);
 busystate = bs_to_exchange_bs(busystate, event->busy_state);

 ast_str_append(&body, 0,
 "<?xml version=\"1.0\"?>\n"
 "<a:propertyupdate\n"
 " xmlns:a=\"DAV:\"\n"
 " xmlns:e=\"http://schemas.microsoft.com/exchange/\"\n"
 " xmlns:mapi=\"http://schemas.microsoft.com/mapi/\"\n"
 " xmlns:mapit=\"http://schemas.microsoft.com/mapi/proptag/\"\n"
 " xmlns:x=\"xml:\" xmlns:cal=\"urn:schemas:calendar:\"\n"
 " xmlns:dt=\"uuid:%s/\"\n" /* uid */
 " xmlns:header=\"urn:schemas:mailheader:\"\n"
 " xmlns:mail=\"urn:schemas:httpmail:\"\n"
 ">\n"
 " <a:set>\n"
 " <a:prop>\n"
 " <a:contentclass>urn:content-classes:appointment</a:contentclass>\n"
 " <e:outlookmessageclass>IPM.Appointment</e:outlookmessageclass>\n"
 " <mail:subject>%s</mail:subject>\n" /* summary */
 " <mail:description>%s</mail:description>\n" /* description */
 " <header:to>%s</header:to>\n" /* organizer */
 " <cal:location>%s</cal:location>\n" /* location */
 " <cal:dtstart dt:dt=\"dateTime.tz\">%s</cal:dtstart>\n" /* start */
 " <cal:dtend dt:dt=\"dateTime.tz\">%s</cal:dtend>\n" /* end */
 " <cal:instancetype dt:dt=\"int\">0</cal:instancetype>\n"
 " <cal:busystatus>%s</cal:busystatus>\n" /* busy_state (BUSY, FREE, BUSY_TENTATIVE) */
 " <cal:meetingstatus>CONFIRMED</cal:meetingstatus>\n"
 " <cal:alldayevent dt:dt=\"boolean\">0</cal:alldayevent>\n" /* XXX need to add event support for all day events */
 " <cal:responserequested dt:dt=\"boolean\">0</cal:responserequested>\n"
 " <mapi:finvited dt:dt=\"boolean\">1</mapi:finvited>\n"
 " </a:prop>\n"
 " </a:set>\n"
 "</a:propertyupdate>\n",
 ast_str_buffer(uid),
 ast_str_buffer(summary),
 ast_str_buffer(description),
 ast_str_buffer(organizer),
 ast_str_buffer(location),
 ast_str_buffer(start),
 ast_str_buffer(end),
 ast_str_buffer(busystate));
 ast_verb(0, "\n\n%s\n\n", ast_str_buffer(body));
 ast_str_set(&subdir, 0, "/Calendar/%s.eml", ast_str_buffer(uid));

 if ((response = exchangecal_request(event->owner->tech_pvt, "PROPPATCH", body, subdir))) {
 ret = 0;
 }

write_cleanup:
 ast_free(uid);
 ast_free(summary);
 ast_free(description);
 ast_free(organizer);
 ast_free(location);
 ast_free(start);
 ast_free(end);
 ast_free(busystate);
 ast_free(body);
 ast_free(response);
 ast_free(subdir);

 return ret;
}


static struct ast_str *exchangecal_get_events_between(struct exchangecal_pvt *pvt, time_t start_time, time_t end_time)
{
 struct ast_str *body, *response;
 char start[80], end[80];
 struct timeval tv = {0,};
 struct ast_tm tm;

 tv.tv_sec = start_time;
 ast_localtime(&tv, &tm, "UTC");
 ast_strftime(start, sizeof(start), "%Y/%m/%d %T", &tm);

 tv.tv_sec = end_time;
 ast_localtime(&tv, &tm, "UTC");
 ast_strftime(end, sizeof(end), "%Y/%m/%d %T", &tm);

 if (!(body = ast_str_create(512))) {
 ast_log(LOG_ERROR, "Could not allocate memory for body of request!\n");
 return NULL;
 }

 ast_str_append(&body, 0,
 "<?xml version=\"1.0\"?>\n"
 "<g:searchrequest xmlns:g=\"DAV:\">\n"
 " <g:sql> SELECT \"urn:schemas:calendar:location\", \"urn:schemas:httpmail:subject\",\n"
 " \"urn:schemas:calendar:dtstart\", \"urn:schemas:calendar:dtend\",\n"
 " \"urn:schemas:calendar:busystatus\", \"urn:schemas:calendar:instancetype\",\n"
 " \"urn:schemas:calendar:uid\", \"urn:schemas:httpmail:textdescription\",\n"
 " \"urn:schemas:calendar:organizer\", \"urn:schemas:calendar:reminderoffset\"\n"
 " FROM Scope('SHALLOW TRAVERSAL OF \"%s/Calendar\"')\n"
 " WHERE NOT \"urn:schemas:calendar:instancetype\" = 1\n"
 " AND \"DAV:contentclass\" = 'urn:content-classes:appointment'\n"
 " AND NOT (\"urn:schemas:calendar:dtend\" &lt; '%s'\n"
 " OR \"urn:schemas:calendar:dtstart\" &gt; '%s')\n"
 " ORDER BY \"urn:schemas:calendar:dtstart\" ASC\n"
 " </g:sql>\n"
 "</g:searchrequest>\n", pvt->url, start, end);

 ast_debug(5, "Request:\n%s\n", ast_str_buffer(body));
 response = exchangecal_request(pvt, "SEARCH", body, NULL);
 ast_debug(5, "Response:\n%s\n", ast_str_buffer(response));
 ast_free(body);

 return response;
}

static int update_exchangecal(struct exchangecal_pvt *pvt)
{
 struct xmlstate state;
 struct timeval now = ast_tvnow();
 time_t start, end;
 struct ast_str *response;
 iksparser *p;

 state.pvt = pvt;
 start = now.tv_sec;
 end = now.tv_sec + 60 * pvt->owner->timeframe;
 if (!(response = exchangecal_get_events_between(pvt, start, end))) {
 return -1;
 }

 p = iks_sax_new(&state, parse_tag, parse_cdata);
 iks_parse(p, ast_str_buffer(response), ast_str_strlen(response), 1);
 ast_calendar_merge_events(pvt->owner, pvt->events);
 ast_free(response);

 return 0;
}

static void *exchangecal_load_calendar(void *void_data)
{
 struct exchangecal_pvt *pvt;
 const struct ast_config *cfg;
 struct ast_variable *v;
 struct ast_calendar *cal = void_data;
 ast_mutex_t refreshlock;

 if (!(cal && (cfg = ast_calendar_config_acquire()))) {
 ast_log(LOG_ERROR, "You must enable calendar support for res_exchangecal to load\n");
 return NULL;
 }

 if (ao2_trylock(cal)) {
 if (cal->unloading) {
 ast_log(LOG_WARNING, "Unloading module, load_calendar cancelled.\n");
 } else {
 ast_log(LOG_WARNING, "Could not lock calendar, aborting!\n");
 }
 ast_calendar_config_release();
 return NULL;
 }

 if (!(pvt = ao2_alloc(sizeof(*pvt), exchangecal_destructor))) {
 ast_log(LOG_ERROR, "Could not allocate exchangecal_pvt structure for calendar: %s\n", cal->name);
 ast_calendar_config_release();
 return NULL;
 }

 pvt->owner = cal;

 if (!(pvt->events = ast_calendar_event_container_alloc())) {
 ast_log(LOG_ERROR, "Could not allocate space for fetching events for calendar: %s\n", cal->name);
 pvt = unref_exchangecal(pvt);
 ao2_unlock(cal);
 ast_calendar_config_release();
 return NULL;
 }

 if (ast_string_field_init(pvt, 32)) {
 ast_log(LOG_ERROR, "Couldn't allocate string field space for calendar: %s\n", cal->name);
 pvt = unref_exchangecal(pvt);
 ao2_unlock(cal);
 ast_calendar_config_release();
 return NULL;
 }

 for (v = ast_variable_browse(cfg, cal->name); v; v = v->next) {
 if (!strcasecmp(v->name, "url")) {
 ast_string_field_set(pvt, url, v->value);
 } else if (!strcasecmp(v->name, "user")) {
 ast_string_field_set(pvt, user, v->value);
 } else if (!strcasecmp(v->name, "secret")) {
 ast_string_field_set(pvt, secret, v->value);
 }
 }

 ast_calendar_config_release();

 if (ast_strlen_zero(pvt->url)) {
 ast_log(LOG_WARNING, "No URL was specified for Exchange calendar '%s' - skipping.\n", cal->name);
 pvt = unref_exchangecal(pvt);
 ao2_unlock(cal);
 return NULL;
 }

 if (ne_uri_parse(pvt->url, &pvt->uri) || pvt->uri.host == NULL || pvt->uri.path == NULL) {
 ast_log(LOG_WARNING, "Could not parse url '%s' for Exchange calendar '%s' - skipping.\n", pvt->url, cal->name);
 pvt = unref_exchangecal(pvt);
 ao2_unlock(cal);
 return NULL;
 }

 if (pvt->uri.scheme == NULL) {
 pvt->uri.scheme = "http";
 }

 if (pvt->uri.port == 0) {
 pvt->uri.port = ne_uri_defaultport(pvt->uri.scheme);
 }

 pvt->session = ne_session_create(pvt->uri.scheme, pvt->uri.host, pvt->uri.port);
 ne_redirect_register(pvt->session);
 ne_set_server_auth(pvt->session, auth_credentials, pvt);
 if (!strcasecmp(pvt->uri.scheme, "https")) {
 ne_ssl_trust_default_ca(pvt->session);
 }

 cal->tech_pvt = pvt;

 ast_mutex_init(&refreshlock);

 /* Load it the first time */
 update_exchangecal(pvt);

 ao2_unlock(cal);

 /* The only writing from another thread will be if unload is true */
 for (;;) {
 struct timeval tv = ast_tvnow();
 struct timespec ts = {0,};

 ts.tv_sec = tv.tv_sec + (60 * pvt->owner->refresh);

 ast_mutex_lock(&refreshlock);
 while (!pvt->owner->unloading) {
 if (ast_cond_timedwait(&pvt->owner->unload, &refreshlock, &ts) == ETIMEDOUT) {
 break;
 }
 }
 ast_mutex_unlock(&refreshlock);

 if (pvt->owner->unloading) {
 ast_debug(10, "Skipping refresh since we got a shutdown signal\n");
 return NULL;
 }

 ast_debug(10, "Refreshing after %d minute timeout\n", pvt->owner->refresh);

 update_exchangecal(pvt);
 }

 return NULL;
}

static int load_module(void)
{
 ne_sock_init();
 if (ast_calendar_register(&exchangecal_tech)) {
 ne_sock_exit();
 return AST_MODULE_LOAD_DECLINE;
 }

 return AST_MODULE_LOAD_SUCCESS;
}

static int unload_module(void)
{
 ast_calendar_unregister(&exchangecal_tech);
 ne_sock_exit();
 return 0;
}

AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "Asterisk MS Exchange Calendar Integration",
 .support_level = AST_MODULE_SUPPORT_EXTENDED,
 .load = load_module,
 .unload = unload_module,
 .load_pri = AST_MODPRI_DEVSTATE_PLUGIN,
 .requires = "res_calendar",
);