res_pjsip_registrar.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2013, Digium, Inc.
 *
 * Joshua Colp <[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.
 */

/*** MODULEINFO
   <depend>pjproject</depend>
   <depend>res_pjproject</depend>
   <depend>res_pjsip</depend>
   <support_level>core</support_level>
 ***/

#include "asterisk.h"

#include <signal.h>
#include <pjsip.h>
#include <pjsip_ua.h>

#include "asterisk/res_pjsip.h"
#include "asterisk/module.h"
#include "asterisk/paths.h"
#include "asterisk/test.h"
#include "asterisk/taskprocessor.h"
#include "asterisk/manager.h"
#include "asterisk/named_locks.h"
#include "asterisk/res_pjproject.h"
#include "res_pjsip/include/res_pjsip_private.h"

/*** DOCUMENTATION
   <manager name="PJSIPShowRegistrationsInbound" language="en_US">
      <synopsis>
         Lists PJSIP inbound registrations.
      </synopsis>
      <syntax />
      <description>
         <para>
         In response, <literal>InboundRegistrationDetail</literal> events showing configuration
         and status information are raised for all contacts, static or dynamic.  Once all events
         are completed an <literal>InboundRegistrationDetailComplete</literal> is issued.
         </para>
         <warning><para>
            This command just dumps all coonfigured AORs with contacts, even if the contact
            is a permanent one.  To really get just inbound registrations, use
            <literal>PJSIPShowRegistrationInboundContactStatuses</literal>.
         </para>
         </warning>
      </description>
      <see-also>
         <ref type="manager" module="res_pjsip_registrar">PJSIPShowRegistrationInboundContactStatuses</ref>
      </see-also>
   </manager>
   <manager name="PJSIPShowRegistrationInboundContactStatuses" language="en_US">
      <synopsis>
         Lists ContactStatuses for PJSIP inbound registrations.
      </synopsis>
      <syntax />
      <description>
         <para>
         In response, <literal>ContactStatusDetail</literal> events showing status information
         are raised for each inbound registration (dynamic contact) object.  Once all events
         are completed a <literal>ContactStatusDetailComplete</literal> event is issued.
         </para>
      </description>
   </manager>
 ***/

static int pj_max_hostname = PJ_MAX_HOSTNAME;
static int pjsip_max_url_size = PJSIP_MAX_URL_SIZE;

/*! \brief Internal function which returns the expiration time for a contact */
static unsigned int registrar_get_expiration(const struct ast_sip_aor *aor, const pjsip_contact_hdr *contact, const pjsip_rx_data *rdata)
{
   pjsip_expires_hdr *expires;
   unsigned int expiration = aor->default_expiration;

   if (contact && contact->expires != PJSIP_EXPIRES_NOT_SPECIFIED) {
      /* Expiration was provided with the contact itself */
      expiration = contact->expires;
   } else if ((expires = pjsip_msg_find_hdr(rdata->msg_info.msg, PJSIP_H_EXPIRES, NULL))) {
      /* Expiration was provided using the Expires header */
      expiration = expires->ivalue;
   }

   /* If the value has explicitly been set to 0, do not enforce */
   if (!expiration) {
      return expiration;
   }

   /* Enforce the range that we will allow for expiration */
   if (expiration < aor->minimum_expiration) {
      expiration = aor->minimum_expiration;
   } else if (expiration > aor->maximum_expiration) {
      expiration = aor->maximum_expiration;
   }

   return expiration;
}

/*! \brief Structure used for finding contact */
struct registrar_contact_details {
   /*! \brief Pool used for parsing URI */
   pj_pool_t *pool;
   /*! \brief URI being looked for */
   pjsip_sip_uri *uri;
};

/*! \brief Callback function for finding a contact */
static int registrar_find_contact(void *obj, void *arg, int flags)
{
   struct ast_sip_contact *contact = obj;
   const struct registrar_contact_details *details = arg;
   pjsip_uri *contact_uri;

   if (ast_tvzero(contact->expiration_time)) {
      return 0;
   }

   contact_uri = pjsip_parse_uri(details->pool, (char*)contact->uri, strlen(contact->uri), 0);
   if (!contact_uri) {
      ast_log(LOG_WARNING, "Unable to parse contact URI from '%s'.\n", contact->uri);
      return 0;
   }

   return (pjsip_uri_cmp(PJSIP_URI_IN_CONTACT_HDR, details->uri, contact_uri) == PJ_SUCCESS) ? CMP_MATCH : 0;
}

/*! \brief Internal function which validates provided Contact headers to confirm that they are acceptable, and returns number of contacts */
static int registrar_validate_contacts(const pjsip_rx_data *rdata, pj_pool_t *pool, struct ao2_container *contacts,
   struct ast_sip_aor *aor, int permanent, int *added, int *updated, int *deleted)
{
   pjsip_contact_hdr *previous = NULL;
   pjsip_contact_hdr *contact = (pjsip_contact_hdr *)&rdata->msg_info.msg->hdr;
   struct registrar_contact_details details = {
      .pool = pool,
   };

   for (; (contact = (pjsip_contact_hdr *) pjsip_msg_find_hdr(rdata->msg_info.msg, PJSIP_H_CONTACT, contact->next)); pj_pool_reset(pool)) {
      unsigned int expiration = registrar_get_expiration(aor, contact, rdata);
      struct ast_sip_contact *existing;
      char contact_uri[pjsip_max_url_size];

      if (contact->star) {
         /* The expiration MUST be 0 when a '*' contact is used and there must be no other contact */
         if (expiration != 0 || previous) {
            return -1;
         }
         /* Count all contacts to delete */
         *deleted = ao2_container_count(contacts) - permanent;
         previous = contact;
         continue;
      } else if (previous && previous->star) {
         /* If there is a previous contact and it is a '*' this is a deal breaker */
         return -1;
      }
      previous = contact;

      if (!PJSIP_URI_SCHEME_IS_SIP(contact->uri) && !PJSIP_URI_SCHEME_IS_SIPS(contact->uri)) {
         continue;
      }

      details.uri = pjsip_uri_get_uri(contact->uri);

      /* pjsip_uri_print returns -1 if there's not enough room in the buffer */
      if (pjsip_uri_print(PJSIP_URI_IN_CONTACT_HDR, details.uri, contact_uri, sizeof(contact_uri)) < 0) {
         /* If the total length of the uri is greater than pjproject can handle, go no further */
         return -1;
      }

      if (details.uri->host.slen >= pj_max_hostname) {
         /* If the length of the hostname is greater than pjproject can handle, go no further */
         return -1;
      }

      /* Determine if this is an add, update, or delete for policy enforcement purposes */
      existing = ao2_callback(contacts, 0, registrar_find_contact, &details);
      ao2_cleanup(existing);
      if (!existing) {
         if (expiration) {
            ++*added;
         }
      } else if (expiration) {
         ++*updated;
      } else {
         ++*deleted;
      }
   }

   return 0;
}

enum contact_delete_type {
   CONTACT_DELETE_ERROR,
   CONTACT_DELETE_EXISTING,
   CONTACT_DELETE_EXPIRE,
   CONTACT_DELETE_REQUEST,
   CONTACT_DELETE_SHUTDOWN,
};

static int registrar_contact_delete(enum contact_delete_type type, pjsip_transport *transport,
   struct ast_sip_contact *contact, const char *aor_name);

/*! \brief Internal function used to delete a contact from an AOR */
static int registrar_delete_contact(void *obj, void *arg, int flags)
{
   return registrar_contact_delete(
      CONTACT_DELETE_REQUEST, NULL, obj, arg) ? 0 : CMP_MATCH;
}

/*! \brief Internal function which adds a contact to a response */
static int registrar_add_contact(void *obj, void *arg, int flags)
{
   struct ast_sip_contact *contact = obj;
   pjsip_tx_data *tdata = arg;
   pj_str_t uri;
   pjsip_uri *parsed;

   pj_strdup2_with_null(tdata->pool, &uri, contact->uri);
   parsed = pjsip_parse_uri(tdata->pool, uri.ptr, uri.slen, PJSIP_PARSE_URI_AS_NAMEADDR);

   if (parsed && (PJSIP_URI_SCHEME_IS_SIP(parsed) || PJSIP_URI_SCHEME_IS_SIPS(parsed))) {
      pjsip_contact_hdr *hdr = pjsip_contact_hdr_create(tdata->pool);
      hdr->uri = parsed;
      if (!ast_tvzero(contact->expiration_time)) {
         hdr->expires = ast_tvdiff_ms(contact->expiration_time, ast_tvnow()) / 1000;
      } else {
         hdr->expires = PJSIP_EXPIRES_NOT_SPECIFIED;
      }
      pjsip_msg_add_hdr(tdata->msg, (pjsip_hdr *) hdr);
   } else {
      ast_log(LOG_WARNING, "Skipping invalid Contact URI \"%.*s\" for AOR %s\n",
         (int) uri.slen, uri.ptr, contact->aor);
   }

   return 0;
}

static const pj_str_t path_hdr_name = { "Path", 4 };

static int build_path_data(pjsip_rx_data *rdata, struct ast_str **path_str)
{
   pjsip_generic_string_hdr *path_hdr = pjsip_msg_find_hdr_by_name(rdata->msg_info.msg, &path_hdr_name, NULL);

   if (!path_hdr) {
      return 0;
   }

   *path_str = ast_str_create(64);
   if (!*path_str) {
      return -1;
   }

   ast_str_set(path_str, 0, "%.*s", (int)path_hdr->hvalue.slen, path_hdr->hvalue.ptr);

   while ((path_hdr = (pjsip_generic_string_hdr *) pjsip_msg_find_hdr_by_name(rdata->msg_info.msg, &path_hdr_name, path_hdr->next))) {
      ast_str_append(path_str, 0, ",%.*s", (int)path_hdr->hvalue.slen, path_hdr->hvalue.ptr);
   }

   return 0;
}

static int registrar_validate_path(pjsip_rx_data *rdata, struct ast_sip_aor *aor, struct ast_str **path_str)
{
   const pj_str_t path_supported_name = { "path", 4 };
   pjsip_supported_hdr *supported_hdr;
   int i;

   if (!aor->support_path) {
      return 0;
   }

   if (build_path_data(rdata, path_str)) {
      return -1;
   }

   if (!*path_str) {
      return 0;
   }

   supported_hdr = pjsip_msg_find_hdr(rdata->msg_info.msg, PJSIP_H_SUPPORTED, NULL);
   if (!supported_hdr) {
      return -1;
   }

   /* Find advertised path support */
   for (i = 0; i < supported_hdr->count; i++) {
      if (!pj_stricmp(&supported_hdr->values[i], &path_supported_name)) {
         return 0;
      }
   }

   /* Path header present, but support not advertised */
   return -1;
}

/*! Transport monitor for incoming REGISTER contacts */
struct contact_transport_monitor {
   /*!
    * \brief Sorcery contact name to remove on transport shutdown
    * \note Stored after aor_name in space reserved when struct allocated.
    */
   char *contact_name;
   /*! Indicates that the monitor is in the process of removing a contact */
   int removing;
   /*! AOR name the contact is associated */
   char aor_name[0];
};

static int contact_transport_monitor_matcher(void *a, void *b)
{
   struct contact_transport_monitor *ma = a;
   struct contact_transport_monitor *mb = b;

   return strcmp(ma->aor_name, mb->aor_name) == 0
      && strcmp(ma->contact_name, mb->contact_name) == 0;
}

static int register_contact_transport_remove_cb(void *data)
{
   struct contact_transport_monitor *monitor = data;
   struct ast_sip_contact *contact;
   struct ast_sip_aor *aor;

   aor = ast_sip_location_retrieve_aor(monitor->aor_name);
   if (!aor) {
      ao2_lock(monitor);
      monitor->removing = 0;
      ao2_unlock(monitor);
      ao2_ref(monitor, -1);
      return 0;
   }

   ao2_lock(aor);

   contact = ast_sip_location_retrieve_contact(monitor->contact_name);
   if (contact) {
      registrar_contact_delete(CONTACT_DELETE_SHUTDOWN, NULL, contact, monitor->aor_name);
      ao2_ref(contact, -1);
   }
   ao2_unlock(aor);
   ao2_ref(aor, -1);

   ao2_ref(monitor, -1);
   return 0;
}

/*!
 * \internal
 * \brief The reliable transport we registered as a contact has shutdown.
 *
 * \param data What contact needs to be removed.
 *
 * \note Normally executed by the pjsip monitor thread.
 *
 * \return Nothing
 */
static void register_contact_transport_shutdown_cb(void *data)
{
   struct contact_transport_monitor *monitor = data;

   /*
    * It's possible for this shutdown handler to get called multiple times for the
    * same monitor from different threads. Only one of the calls needs to do the
    * actual removing of the contact, so if one is currently removing then any
    * subsequent calls can skip.
    */
   ao2_lock(monitor);
   if (monitor->removing) {
      ao2_unlock(monitor);
      return;
   }

   monitor->removing = 1;

   /*
    * Push off to a default serializer.  This is in case sorcery
    * does database accesses for contacts.  Database accesses may
    * not be on this machine.  We don't want to tie up the pjsip
    * monitor thread with potentially long access times.
    */
   ao2_ref(monitor, +1);
   if (ast_sip_push_task(NULL, register_contact_transport_remove_cb, monitor)) {
      monitor->removing = 0;
      ao2_ref(monitor, -1);
   }

   ao2_unlock(monitor);
}


static int registrar_contact_delete(enum contact_delete_type type, pjsip_transport *transport,
   struct ast_sip_contact *contact, const char *aor_name)
{
   int aor_size;

   /* Permanent contacts can't be deleted */
   if (ast_tvzero(contact->expiration_time)) {
      return -1;
   }

   aor_size = aor_name ? strlen(aor_name) : 0;
   if (contact->prune_on_boot && type != CONTACT_DELETE_SHUTDOWN && aor_size) {
      const char *contact_name = ast_sorcery_object_get_id(contact);
      size_t contact_name_len = strlen(contact_name) + 1;
      struct contact_transport_monitor *monitor = ast_alloca(
         sizeof(*monitor) + 1 + aor_size + contact_name_len);

      strcpy(monitor->aor_name, aor_name); /* Safe */
      monitor->contact_name = monitor->aor_name + aor_size + 1;
      ast_copy_string(monitor->contact_name, contact_name, contact_name_len); /* Safe */

      if (transport) {
         ast_sip_transport_monitor_unregister(transport,
            register_contact_transport_shutdown_cb,   monitor,
            contact_transport_monitor_matcher);
      } else {
         /*
          * If a specific transport is not supplied then unregister the matching
          * monitor from all reliable transports.
          */
         ast_sip_transport_monitor_unregister_all(register_contact_transport_shutdown_cb,
            monitor, contact_transport_monitor_matcher);
      }
   }

   ast_sip_location_delete_contact(contact);

   if (aor_size) {
      if (VERBOSITY_ATLEAST(3)) {
         const char *reason = "none";

         switch (type) {
         case CONTACT_DELETE_ERROR:
            reason = "registration failure";
            break;
         case CONTACT_DELETE_EXISTING:
            reason = "remove existing";
            break;
         case CONTACT_DELETE_EXPIRE:
            reason = "expiration";
            break;
         case CONTACT_DELETE_REQUEST:
            reason = "request";
            break;
         case CONTACT_DELETE_SHUTDOWN:
            reason = "shutdown";
            break;
         }

         ast_verb(3, "Removed contact '%s' from AOR '%s' due to %s\n",
                contact->uri, aor_name, reason);
      }

      ast_test_suite_event_notify("AOR_CONTACT_REMOVED",
            "Contact: %s\r\n"
            "AOR: %s\r\n"
            "UserAgent: %s",
            contact->uri,
            aor_name,
            contact->user_agent);
   }

   return 0;
}

AST_VECTOR(excess_contact_vector, struct ast_sip_contact *);

static int vec_contact_cmp(struct ast_sip_contact *left, struct ast_sip_contact *right)
{
   struct ast_sip_contact *left_contact = left;
   struct ast_sip_contact *right_contact = right;

   /* Sort from soonest to expire to last to expire */
   return ast_tvcmp(left_contact->expiration_time, right_contact->expiration_time);
}

static int vec_contact_add(void *obj, void *arg, int flags)
{
   struct ast_sip_contact *contact = obj;
   struct excess_contact_vector *contact_vec = arg;

   /*
    * Performance wise, an insertion sort is fine because we
    * shouldn't need to remove more than a handful of contacts.
    * I expect we'll typically be removing only one contact.
    */
   AST_VECTOR_ADD_SORTED(contact_vec, contact, vec_contact_cmp);
   if (AST_VECTOR_SIZE(contact_vec) == AST_VECTOR_MAX_SIZE(contact_vec)) {
      /*
       * We added a contact over the number we need to remove.
       * Remove the longest to expire contact from the vector
       * which is the last element in the vector.  It may be
       * the one we just added or the one we just added pushed
       * out an earlier contact from removal consideration.
       */
      --AST_VECTOR_SIZE(contact_vec);
   }
   return 0;
}

/*!
 * \internal
 * \brief Remove excess existing contacts that expire the soonest.
 * \since 13.18.0
 *
 * \param contacts Container of unmodified contacts that could remove.
 * \param to_remove Maximum number of contacts to remove.
 *
 * \return Nothing
 */
static void remove_excess_contacts(struct ao2_container *contacts, struct ao2_container *response_contacts,
   unsigned int to_remove)
{
   struct excess_contact_vector contact_vec;

   /*
    * Create a sorted vector to hold the to_remove soonest to
    * expire contacts.  The vector has an extra space to
    * temporarily hold the longest to expire contact that we
    * won't remove.
    */
   if (AST_VECTOR_INIT(&contact_vec, to_remove + 1)) {
      return;
   }
   ao2_callback(contacts, OBJ_NODATA | OBJ_MULTIPLE, vec_contact_add, &contact_vec);

   /*
    * The vector should always be populated with the number
    * of contacts we need to remove.  Just in case, we will
    * remove all contacts in the vector even if the contacts
    * container had fewer contacts than there should be.
    */
   ast_assert(AST_VECTOR_SIZE(&contact_vec) == to_remove);
   to_remove = AST_VECTOR_SIZE(&contact_vec);

   /* Remove the excess contacts that expire the soonest */
   while (to_remove--) {
      struct ast_sip_contact *contact;

      contact = AST_VECTOR_GET(&contact_vec, to_remove);

      registrar_contact_delete(CONTACT_DELETE_EXISTING, NULL, contact, contact->aor);

      ao2_unlink(response_contacts, contact);
   }

   AST_VECTOR_FREE(&contact_vec);
}

/*! \brief Callback function which adds non-permanent contacts to a container */
static int registrar_add_non_permanent(void *obj, void *arg, int flags)
{
   struct ast_sip_contact *contact = obj;
   struct ao2_container *container = arg;

   if (ast_tvzero(contact->expiration_time)) {
      return 0;
   }

   ao2_link(container, contact);

   return 0;
}

struct aor_core_response {
   /*! Tx data to use for statefull response.  NULL for stateless response. */
   pjsip_tx_data *tdata;
   /*! SIP response code to send in stateless response */
   int code;
};

static void register_aor_core(pjsip_rx_data *rdata,
   struct ast_sip_endpoint *endpoint,
   struct ast_sip_aor *aor,
   const char *aor_name,
   struct ao2_container *contacts,
   struct aor_core_response *response)
{
   static const pj_str_t USER_AGENT = { "User-Agent", 10 };

   int added = 0;
   int updated = 0;
   int deleted = 0;
   int permanent = 0;
   int contact_count;
   struct ao2_container *existing_contacts = NULL;
   pjsip_contact_hdr *contact_hdr = (pjsip_contact_hdr *)&rdata->msg_info.msg->hdr;
   struct registrar_contact_details details = { 0, };
   pjsip_tx_data *tdata;
   RAII_VAR(struct ast_str *, path_str, NULL, ast_free);
   struct ast_sip_contact *response_contact;
   char *user_agent = NULL;
   pjsip_user_agent_hdr *user_agent_hdr;
   pjsip_expires_hdr *expires_hdr;
   pjsip_via_hdr *via_hdr;
   pjsip_via_hdr *via_hdr_last;
   char *via_addr = NULL;
   int via_port = 0;
   pjsip_cid_hdr *call_id_hdr;
   char *call_id = NULL;
   size_t alloc_size;

   /* We create a single pool and use it throughout this function where we need one */
   details.pool = pjsip_endpt_create_pool(ast_sip_get_pjsip_endpoint(),
      "Contact Comparison", 1024, 256);
   if (!details.pool) {
      response->code = 500;
      return;
   }

   /* If there are any permanent contacts configured on the AOR we need to take them
    * into account when counting contacts.
    */
   if (aor->permanent_contacts) {
      permanent = ao2_container_count(aor->permanent_contacts);
   }

   if (registrar_validate_contacts(rdata, details.pool, contacts, aor, permanent, &added, &updated, &deleted)) {
      /* The provided Contact headers do not conform to the specification */
      ast_sip_report_failed_acl(endpoint, rdata, "registrar_invalid_contacts_provided");
      ast_log(LOG_WARNING, "Failed to validate contacts in REGISTER request from '%s'\n",
            ast_sorcery_object_get_id(endpoint));
      response->code = 400;
      pjsip_endpt_release_pool(ast_sip_get_pjsip_endpoint(), details.pool);
      return;
   }

   if (registrar_validate_path(rdata, aor, &path_str)) {
      /* Ensure that intervening proxies did not make invalid modifications to the request */
      ast_log(LOG_WARNING, "Invalid modifications made to REGISTER request from '%s' by intervening proxy\n",
            ast_sorcery_object_get_id(endpoint));
      response->code = 420;
      pjsip_endpt_release_pool(ast_sip_get_pjsip_endpoint(), details.pool);
      return;
   }

   if (aor->remove_existing) {
      /* Cumulative number of contacts affected by this registration */
      contact_count = MAX(updated + added - deleted,  0);

      /* We need to keep track of only existing contacts so we can later
       * remove them if need be.
       */
      existing_contacts = ao2_container_alloc_list(AO2_ALLOC_OPT_LOCK_NOLOCK, 0,
         NULL, ast_sorcery_object_id_compare);
      if (!existing_contacts) {
         response->code = 500;
         pjsip_endpt_release_pool(ast_sip_get_pjsip_endpoint(), details.pool);
         return;
      }

      ao2_callback(contacts, OBJ_NODATA, registrar_add_non_permanent, existing_contacts);
   } else {
      /* Total contacts after this registration */
      contact_count = ao2_container_count(contacts) - permanent + added - deleted;
   }
   if (contact_count > aor->max_contacts) {
      /* Enforce the maximum number of contacts */
      ast_sip_report_failed_acl(endpoint, rdata, "registrar_attempt_exceeds_maximum_configured_contacts");
      ast_log(LOG_WARNING, "Registration attempt from endpoint '%s' (%s:%d) to AOR '%s' will exceed max contacts of %u\n",
            ast_sorcery_object_get_id(endpoint), rdata->pkt_info.src_name, rdata->pkt_info.src_port,
            aor_name, aor->max_contacts);
      response->code = 403;
      pjsip_endpt_release_pool(ast_sip_get_pjsip_endpoint(), details.pool);
      ao2_cleanup(existing_contacts);
      return;
   }

   user_agent_hdr = pjsip_msg_find_hdr_by_name(rdata->msg_info.msg, &USER_AGENT, NULL);
   if (user_agent_hdr) {
      alloc_size = pj_strlen(&user_agent_hdr->hvalue) + 1;
      user_agent = ast_alloca(alloc_size);
      ast_copy_pj_str(user_agent, &user_agent_hdr->hvalue, alloc_size);
   }

   /* Find the first Via header */
   via_hdr = via_hdr_last = (pjsip_via_hdr*) pjsip_msg_find_hdr(rdata->msg_info.msg, PJSIP_H_VIA, NULL);
   if (via_hdr) {
      /* Find the last Via header */
      while ( (via_hdr = (pjsip_via_hdr*) pjsip_msg_find_hdr(rdata->msg_info.msg,
            PJSIP_H_VIA, via_hdr->next)) != NULL) {
         via_hdr_last = via_hdr;
      }
      alloc_size = pj_strlen(&via_hdr_last->sent_by.host) + 1;
      via_addr = ast_alloca(alloc_size);
      ast_copy_pj_str(via_addr, &via_hdr_last->sent_by.host, alloc_size);
      via_port=via_hdr_last->sent_by.port;
   }

   call_id_hdr = (pjsip_cid_hdr*) pjsip_msg_find_hdr(rdata->msg_info.msg, PJSIP_H_CALL_ID, NULL);
   if (call_id_hdr) {
      alloc_size = pj_strlen(&call_id_hdr->id) + 1;
      call_id = ast_alloca(alloc_size);
      ast_copy_pj_str(call_id, &call_id_hdr->id, alloc_size);
   }

   /* Iterate each provided Contact header and add, update, or delete */
   for (; (contact_hdr = (pjsip_contact_hdr *) pjsip_msg_find_hdr(rdata->msg_info.msg, PJSIP_H_CONTACT, contact_hdr->next)); pj_pool_reset(details.pool)) {
      int expiration;
      char contact_uri[pjsip_max_url_size];
      RAII_VAR(struct ast_sip_contact *, contact, NULL, ao2_cleanup);

      if (contact_hdr->star) {
         /* A star means to unregister everything, so do so for the possible contacts */
         ao2_callback(contacts, OBJ_NODATA | OBJ_UNLINK | OBJ_MULTIPLE,
            registrar_delete_contact, (void *)aor_name);
         /* If we are keeping track of existing contacts for removal then, well, there is
          * absolutely nothing left so no need to try to remove any.
          */
         if (existing_contacts) {
            ao2_ref(existing_contacts, -1);
            existing_contacts = NULL;
         }
         break;
      }

      if (!PJSIP_URI_SCHEME_IS_SIP(contact_hdr->uri) && !PJSIP_URI_SCHEME_IS_SIPS(contact_hdr->uri)) {
         /* This registrar only currently supports sip: and sips: URI schemes */
         continue;
      }

      expiration = registrar_get_expiration(aor, contact_hdr, rdata);
      details.uri = pjsip_uri_get_uri(contact_hdr->uri);
      pjsip_uri_print(PJSIP_URI_IN_CONTACT_HDR, details.uri, contact_uri, sizeof(contact_uri));

      contact = ao2_callback(contacts, OBJ_UNLINK, registrar_find_contact, &details);

      /* If a contact was returned and we need to keep track of existing contacts then it
       * should be removed.
       */
      if (contact && existing_contacts) {
         ao2_unlink(existing_contacts, contact);
      }

      if (!contact) {
         int prune_on_boot;

         /* If they are actually trying to delete a contact that does not exist... be forgiving */
         if (!expiration) {
            ast_verb(3, "Attempted to remove non-existent contact '%s' from AOR '%s' by request\n",
               contact_uri, aor_name);
            continue;
         }

         prune_on_boot = !ast_sip_will_uri_survive_restart(details.uri, endpoint, rdata);

         contact = ast_sip_location_create_contact(aor, contact_uri,
            ast_tvadd(ast_tvnow(), ast_samp2tv(expiration, 1)),
            path_str ? ast_str_buffer(path_str) : NULL,
            user_agent, via_addr, via_port, call_id, prune_on_boot, endpoint);
         if (!contact) {
            ast_log(LOG_ERROR, "Unable to bind contact '%s' to AOR '%s'\n",
               contact_uri, aor_name);
            continue;
         }

         if (prune_on_boot) {
            size_t contact_name_len;
            const char *contact_name;
            struct contact_transport_monitor *monitor;

            /*
             * Monitor the transport in case it gets disconnected because
             * the contact won't be valid anymore if that happens.
             */
            contact_name = ast_sorcery_object_get_id(contact);
            contact_name_len = strlen(contact_name) + 1;
            monitor = ao2_alloc(sizeof(*monitor) + 1 + strlen(aor_name)
               + contact_name_len, NULL);
            if (monitor) {
               strcpy(monitor->aor_name, aor_name);/* Safe */
               monitor->contact_name = monitor->aor_name + strlen(aor_name) + 1;
               ast_copy_string(monitor->contact_name, contact_name, contact_name_len);/* Safe */

               ast_sip_transport_monitor_register_replace(rdata->tp_info.transport,
                  register_contact_transport_shutdown_cb, monitor, contact_transport_monitor_matcher);
               ao2_ref(monitor, -1);
            }
         }

         ast_verb(3, "Added contact '%s' to AOR '%s' with expiration of %d seconds\n",
            contact_uri, aor_name, expiration);
         ast_test_suite_event_notify("AOR_CONTACT_ADDED",
               "Contact: %s\r\n"
               "AOR: %s\r\n"
               "Expiration: %d\r\n"
               "UserAgent: %s",
               contact_uri,
               aor_name,
               expiration,
               user_agent);

         ao2_link(contacts, contact);
      } else if (expiration) {
         struct ast_sip_contact *contact_update;

         contact_update = ast_sorcery_copy(ast_sip_get_sorcery(), contact);
         if (!contact_update) {
            ast_log(LOG_ERROR, "Failed to update contact '%s' expiration time to %d seconds.\n",
               contact->uri, expiration);
            continue;
         }

         contact_update->expiration_time = ast_tvadd(ast_tvnow(), ast_samp2tv(expiration, 1));
         contact_update->qualify_frequency = aor->qualify_frequency;
         contact_update->authenticate_qualify = aor->authenticate_qualify;
         if (path_str) {
            ast_string_field_set(contact_update, path, ast_str_buffer(path_str));
         }
         if (user_agent) {
            ast_string_field_set(contact_update, user_agent, user_agent);
         }
         if (!ast_strlen_zero(ast_config_AST_SYSTEM_NAME)) {
            ast_string_field_set(contact_update, reg_server, ast_config_AST_SYSTEM_NAME);
         }

         if (ast_sip_location_update_contact(contact_update)) {
            ast_log(LOG_ERROR, "Failed to update contact '%s' expiration time to %d seconds.\n",
               contact->uri, expiration);
            registrar_contact_delete(CONTACT_DELETE_ERROR, rdata->tp_info.transport,
               contact, aor_name);
            continue;
         }
         ast_debug(3, "Refreshed contact '%s' on AOR '%s' with new expiration of %d seconds\n",
            contact_uri, aor_name, expiration);
         ast_test_suite_event_notify("AOR_CONTACT_REFRESHED",
               "Contact: %s\r\n"
               "AOR: %s\r\n"
               "Expiration: %d\r\n"
               "UserAgent: %s",
               contact_uri,
               aor_name,
               expiration,
               contact_update->user_agent);
         ao2_link(contacts, contact_update);
         ao2_cleanup(contact_update);
      } else {
         registrar_contact_delete(CONTACT_DELETE_REQUEST, rdata->tp_info.transport,
               contact, aor_name);
      }
   }

   pjsip_endpt_release_pool(ast_sip_get_pjsip_endpoint(), details.pool);

   /*
    * If the AOR is configured to remove any contacts over max_contacts
    * that have not been updated/added/deleted as a result of this
    * REGISTER do so.
    *
    * The existing contacts container holds all contacts that were not
    * involved in this REGISTER.
    * The contacts container holds the current contacts of the AOR.
    */
   if (aor->remove_existing && existing_contacts) {
      /* Total contacts after this registration */
      contact_count = ao2_container_count(existing_contacts) + updated + added;
      if (contact_count > aor->max_contacts) {
         /* Remove excess existing contacts that expire the soonest */
         remove_excess_contacts(existing_contacts, contacts, contact_count - aor->max_contacts);
      }
      ao2_ref(existing_contacts, -1);
   }

   response_contact = ao2_callback(contacts, 0, NULL, NULL);

   /* Send a response containing all of the contacts (including static) that are present on this AOR */
   if (ast_sip_create_response(rdata, 200, response_contact, &tdata) != PJ_SUCCESS) {
      ao2_cleanup(response_contact);
      ao2_cleanup(contacts);
      response->code = 500;
      return;
   }
   ao2_cleanup(response_contact);

   /* Add the date header to the response, some UAs use this to set their date and time */
   ast_sip_add_date_header(tdata);

   ao2_callback(contacts, 0, registrar_add_contact, tdata);

   if ((expires_hdr = pjsip_msg_find_hdr(rdata->msg_info.msg, PJSIP_H_EXPIRES, NULL))) {
      expires_hdr = pjsip_expires_hdr_create(tdata->pool, registrar_get_expiration(aor, NULL, rdata));
      pjsip_msg_add_hdr(tdata->msg, (pjsip_hdr*)expires_hdr);
   }

   response->tdata = tdata;
}

static int register_aor(pjsip_rx_data *rdata,
   struct ast_sip_endpoint *endpoint,
   struct ast_sip_aor *aor,
   const char *aor_name)
{
   struct aor_core_response response = {
      .code = 500,
   };
   struct ao2_container *contacts = NULL;

   ao2_lock(aor);
   contacts = ast_sip_location_retrieve_aor_contacts_nolock(aor);
   if (!contacts) {
      ao2_unlock(aor);
      pjsip_endpt_respond_stateless(ast_sip_get_pjsip_endpoint(),
         rdata, response.code, NULL, NULL, NULL);
      return PJ_TRUE;
   }

   register_aor_core(rdata, endpoint, aor, aor_name, contacts, &response);
   ao2_cleanup(contacts);
   ao2_unlock(aor);

   /* Now send the REGISTER response to the peer */
   if (response.tdata) {
      ast_sip_send_stateful_response(rdata, response.tdata, endpoint);
   } else {
      pjsip_endpt_respond_stateless(ast_sip_get_pjsip_endpoint(),
         rdata, response.code, NULL, NULL, NULL);
   }
   return PJ_TRUE;
}

static int match_aor(const char *aor_name, const char *id)
{
   if (ast_strlen_zero(aor_name)) {
      return 0;
   }

   if (!strcmp(aor_name, id)) {
      ast_debug(3, "Matched id '%s' to aor '%s'\n", id, aor_name);
      return 1;
   }

   return 0;
}

static char *find_aor_name(const pj_str_t *pj_username, const pj_str_t *pj_domain, const char *aors)
{
   char *configured_aors;
   char *aors_buf;
   char *aor_name;
   char *id_domain;
   char *username, *domain;
   struct ast_sip_domain_alias *alias;

   /* Turn these into C style strings for convenience */
   username = ast_alloca(pj_strlen(pj_username) + 1);
   ast_copy_pj_str(username, pj_username, pj_strlen(pj_username) + 1);
   domain = ast_alloca(pj_strlen(pj_domain) + 1);
   ast_copy_pj_str(domain, pj_domain, pj_strlen(pj_domain) + 1);

   id_domain = ast_alloca(strlen(username) + strlen(domain) + 2);
   sprintf(id_domain, "%s@%s", username, domain);

   aors_buf = ast_strdupa(aors);

   /* Look for exact match on username@domain */
   configured_aors = aors_buf;
   while ((aor_name = ast_strip(strsep(&configured_aors, ",")))) {
      if (match_aor(aor_name, id_domain)) {
         return ast_strdup(aor_name);
      }
   }

   /* If there's a domain alias, look for exact match on username@domain_alias */
   alias = ast_sorcery_retrieve_by_id(ast_sip_get_sorcery(), "domain_alias", domain);
   if (alias) {
      char *id_domain_alias = ast_alloca(strlen(username) + strlen(alias->domain) + 2);

      sprintf(id_domain_alias, "%s@%s", username, alias->domain);
      ao2_cleanup(alias);

      configured_aors = strcpy(aors_buf, aors);/* Safe */
      while ((aor_name = ast_strip(strsep(&configured_aors, ",")))) {
         if (match_aor(aor_name, id_domain_alias)) {
            return ast_strdup(aor_name);
         }
      }
   }

   if (ast_strlen_zero(username)) {
      /* No username, no match */
      return NULL;
   }

   /* Look for exact match on username only */
   configured_aors = strcpy(aors_buf, aors);/* Safe */
   while ((aor_name = ast_strip(strsep(&configured_aors, ",")))) {
      if (match_aor(aor_name, username)) {
         return ast_strdup(aor_name);
      }
   }

   return NULL;
}

static struct ast_sip_aor *find_registrar_aor(struct pjsip_rx_data *rdata, struct ast_sip_endpoint *endpoint)
{
   struct ast_sip_aor *aor = NULL;
   char *aor_name = NULL;
   int i;

   for (i = 0; i < AST_VECTOR_SIZE(&endpoint->ident_method_order); ++i) {
      pj_str_t username;
      pjsip_sip_uri *uri;
      pjsip_authorization_hdr *header = NULL;

      switch (AST_VECTOR_GET(&endpoint->ident_method_order, i)) {
      case AST_SIP_ENDPOINT_IDENTIFY_BY_USERNAME:
         uri = pjsip_uri_get_uri(rdata->msg_info.to->uri);

         pj_strassign(&username, &uri->user);

         /*
          * We may want to match without any user options getting
          * in the way.
          *
          * Logic adapted from AST_SIP_USER_OPTIONS_TRUNCATE_CHECK for pj_str_t.
          */
         if (ast_sip_get_ignore_uri_user_options()) {
            pj_ssize_t semi = pj_strcspn2(&username, ";");
            if (semi < pj_strlen(&username)) {
               username.slen = semi;
            }
         }

         aor_name = find_aor_name(&username, &uri->host, endpoint->aors);
         if (aor_name) {
            ast_debug(3, "Matched aor '%s' by To username\n", aor_name);
         }
         break;
      case AST_SIP_ENDPOINT_IDENTIFY_BY_AUTH_USERNAME:
         while ((header = pjsip_msg_find_hdr(rdata->msg_info.msg, PJSIP_H_AUTHORIZATION,
            header ? header->next : NULL))) {
            if (header && !pj_stricmp2(&header->scheme, "digest")) {
               aor_name = find_aor_name(&header->credential.digest.username,
                  &header->credential.digest.realm, endpoint->aors);
               if (aor_name) {
                  ast_debug(3, "Matched aor '%s' by Authentication username\n", aor_name);
                  break;
               }
            }
         }
         break;
      default:
         continue;
      }

      if (aor_name) {
         break;
      }
   }

   if (ast_strlen_zero(aor_name) || !(aor = ast_sip_location_retrieve_aor(aor_name))) {
      /* The provided AOR name was not found (be it within the configuration or sorcery itself) */
      pjsip_endpt_respond_stateless(ast_sip_get_pjsip_endpoint(), rdata, 404, NULL, NULL, NULL);
      ast_sip_report_req_no_support(endpoint, rdata, "registrar_requested_aor_not_found");
      ast_log(LOG_WARNING, "AOR '%s' not found for endpoint '%s' (%s:%d)\n",
         aor_name ?: "", ast_sorcery_object_get_id(endpoint),
         rdata->pkt_info.src_name, rdata->pkt_info.src_port);
   }
   ast_free(aor_name);
   return aor;
}

static pj_bool_t registrar_on_rx_request(struct pjsip_rx_data *rdata)
{
   RAII_VAR(struct ast_sip_endpoint *, endpoint,
       ast_pjsip_rdata_get_endpoint(rdata), ao2_cleanup);
   struct ast_sip_aor *aor;
   const char *aor_name;

   if (pjsip_method_cmp(&rdata->msg_info.msg->line.req.method, &pjsip_register_method) || !endpoint) {
      return PJ_FALSE;
   }

   if (ast_strlen_zero(endpoint->aors)) {
      /* Short circuit early if the endpoint has no AORs configured on it, which means no registration possible */
      pjsip_endpt_respond_stateless(ast_sip_get_pjsip_endpoint(), rdata, 403, NULL, NULL, NULL);
      ast_sip_report_failed_acl(endpoint, rdata, "registrar_attempt_without_configured_aors");
      ast_log(LOG_WARNING, "Endpoint '%s' (%s:%d) has no configured AORs\n", ast_sorcery_object_get_id(endpoint),
         rdata->pkt_info.src_name, rdata->pkt_info.src_port);
      return PJ_TRUE;
   }

   if (!PJSIP_URI_SCHEME_IS_SIP(rdata->msg_info.to->uri) && !PJSIP_URI_SCHEME_IS_SIPS(rdata->msg_info.to->uri)) {
      pjsip_endpt_respond_stateless(ast_sip_get_pjsip_endpoint(), rdata, 416, NULL, NULL, NULL);
      ast_sip_report_failed_acl(endpoint, rdata, "registrar_invalid_uri_in_to_received");
      ast_log(LOG_WARNING, "Endpoint '%s' (%s:%d) attempted to register to an AOR with a non-SIP URI\n", ast_sorcery_object_get_id(endpoint),
         rdata->pkt_info.src_name, rdata->pkt_info.src_port);
      return PJ_TRUE;
   }

   aor = find_registrar_aor(rdata, endpoint);
   if (!aor) {
      /* We've already responded about not finding an AOR. */
      return PJ_TRUE;
   }

   aor_name = ast_sorcery_object_get_id(aor);

   if (!aor->max_contacts) {
      /* Registration is not permitted for this AOR */
      pjsip_endpt_respond_stateless(ast_sip_get_pjsip_endpoint(), rdata, 403, NULL, NULL, NULL);
      ast_sip_report_req_no_support(endpoint, rdata, "registrar_attempt_without_registration_permitted");
      ast_log(LOG_WARNING, "AOR '%s' has no configured max_contacts. Endpoint '%s' (%s:%d) unable to register\n",
         aor_name, ast_sorcery_object_get_id(endpoint),
         rdata->pkt_info.src_name, rdata->pkt_info.src_port);
   } else {
      register_aor(rdata, endpoint, aor, aor_name);
   }
   ao2_ref(aor, -1);
   return PJ_TRUE;
}

/* function pointer to callback needs to be within the module
   in order to avoid problems with an undefined symbol */
static int sip_contact_to_str(void *acp, void *arg, int flags)
{
   return ast_sip_contact_to_str(acp, arg, flags);
}

static int ami_registrations_aor(void *obj, void *arg, int flags)
{
   struct ast_sip_aor *aor = obj;
   struct ast_sip_ami *ami = arg;
   int *count = ami->arg;
   RAII_VAR(struct ast_str *, buf,
       ast_sip_create_ami_event("InboundRegistrationDetail", ami), ast_free);

   if (!buf) {
      return -1;
   }

   ast_sip_sorcery_object_to_ami(aor, &buf);
   ast_str_append(&buf, 0, "Contacts: ");
   ast_sip_for_each_contact(aor, sip_contact_to_str, &buf);
   ast_str_append(&buf, 0, "\r\n");

   astman_append(ami->s, "%s\r\n", ast_str_buffer(buf));
   (*count)++;
   return 0;
}

static int ami_registrations_endpoint(void *obj, void *arg, int flags)
{
   struct ast_sip_endpoint *endpoint = obj;
   return ast_sip_for_each_aor(
      endpoint->aors, ami_registrations_aor, arg);
}

static int ami_registrations_endpoints(void *arg)
{
   RAII_VAR(struct ao2_container *, endpoints,
       ast_sip_get_endpoints(), ao2_cleanup);

   if (!endpoints) {
      return 0;
   }

   ao2_callback(endpoints, OBJ_NODATA, ami_registrations_endpoint, arg);
   return 0;
}

static int ami_show_registrations(struct mansession *s, const struct message *m)
{
   int count = 0;
   struct ast_sip_ami ami = { .s = s, .m = m, .arg = &count, .action_id = astman_get_header(m, "ActionID"), };

   astman_send_listack(s, m, "Following are Events for each Inbound registration",
      "start");

   ami_registrations_endpoints(&ami);

   astman_send_list_complete_start(s, m, "InboundRegistrationDetailComplete", count);
   astman_send_list_complete_end(s);
   return 0;
}

static int ami_show_registration_contact_statuses(struct mansession *s, const struct message *m)
{
   int count = 0;
   struct ast_sip_ami ami = { .s = s, .m = m, .arg = NULL, .action_id = astman_get_header(m, "ActionID"), };
   struct ao2_container *contacts = ast_sorcery_retrieve_by_fields(
      ast_sip_get_sorcery(), "contact", AST_RETRIEVE_FLAG_MULTIPLE | AST_RETRIEVE_FLAG_ALL, NULL);
   struct ao2_iterator i;
   struct ast_sip_contact *contact;

   astman_send_listack(s, m, "Following are ContactStatusEvents for each Inbound "
             "registration", "start");

   if (contacts) {
      i = ao2_iterator_init(contacts, 0);
      while ((contact = ao2_iterator_next(&i))) {
         struct ast_sip_contact_wrapper wrapper;

         wrapper.aor_id = (char *)contact->aor;
         wrapper.contact = contact;
         wrapper.contact_id = (char *)ast_sorcery_object_get_id(contact);

         ast_sip_format_contact_ami(&wrapper, &ami, 0);
         count++;

         ao2_ref(contact, -1);
      }
      ao2_iterator_destroy(&i);
      ao2_ref(contacts, -1);
   }

   astman_send_list_complete_start(s, m, "ContactStatusDetailComplete", count);
   astman_send_list_complete_end(s);
   return 0;
}

#define AMI_SHOW_REGISTRATION_CONTACT_STATUSES "PJSIPShowRegistrationInboundContactStatuses"
#define AMI_SHOW_REGISTRATIONS "PJSIPShowRegistrationsInbound"

static pjsip_module registrar_module = {
   .name = { "Registrar", 9 },
   .id = -1,
   .priority = PJSIP_MOD_PRIORITY_APPLICATION,
   .on_rx_request = registrar_on_rx_request,
};

/*! \brief Thread keeping things alive */
static pthread_t check_thread = AST_PTHREADT_NULL;

/*! \brief The global interval at which to check for contact expiration */
static unsigned int check_interval;

/*! \brief Callback function which deletes a contact */
static int expire_contact(void *obj, void *arg, int flags)
{
   struct ast_sip_contact *contact = obj;
   struct ast_named_lock *lock;

   lock = ast_named_lock_get(AST_NAMED_LOCK_TYPE_MUTEX, "aor", contact->aor);
   if (!lock) {
      return 0;
   }

   /*
    * We need to check the expiration again with the aor lock held
    * in case another thread is attempting to renew the contact.
    */
   ao2_lock(lock);
   if (ast_tvdiff_ms(ast_tvnow(), contact->expiration_time) > 0) {
      registrar_contact_delete(CONTACT_DELETE_EXPIRE, NULL, contact, contact->aor);
   }
   ao2_unlock(lock);
   ast_named_lock_put(lock);

   return 0;
}

static void *check_expiration_thread(void *data)
{
   struct ao2_container *contacts;
   struct ast_variable *var;
   char *time = alloca(64);

   while (check_interval) {
      sleep(check_interval);

      sprintf(time, "%ld", ast_tvnow().tv_sec);
      var = ast_variable_new("expiration_time <=", time, "");

      ast_debug(4, "Woke up at %s  Interval: %d\n", time, check_interval);

      contacts = ast_sorcery_retrieve_by_fields(ast_sip_get_sorcery(), "contact",
         AST_RETRIEVE_FLAG_MULTIPLE, var);

      ast_variables_destroy(var);
      if (contacts) {
         ast_debug(3, "Expiring %d contacts\n", ao2_container_count(contacts));
         ao2_callback(contacts, OBJ_NODATA, expire_contact, NULL);
         ao2_ref(contacts, -1);
      }
   }

   return NULL;
}

static void expiration_global_loaded(const char *object_type)
{
   check_interval = ast_sip_get_contact_expiration_check_interval();

   /* Observer calls are serialized so this is safe without it's own lock */
   if (check_interval) {
      if (check_thread == AST_PTHREADT_NULL) {
         if (ast_pthread_create_background(&check_thread, NULL, check_expiration_thread, NULL)) {
            ast_log(LOG_ERROR, "Could not create thread for checking contact expiration.\n");
            return;
         }
         ast_debug(3, "Interval = %d, starting thread\n", check_interval);
      }
   } else {
      if (check_thread != AST_PTHREADT_NULL) {
         pthread_kill(check_thread, SIGURG);
         pthread_join(check_thread, NULL);
         check_thread = AST_PTHREADT_NULL;
         ast_debug(3, "Interval = 0, shutting thread down\n");
      }
   }
}

/*! \brief Observer which is used to update our interval when the global setting changes */
static struct ast_sorcery_observer expiration_global_observer = {
   .loaded = expiration_global_loaded,
};

static int load_module(void)
{
   const pj_str_t STR_REGISTER = { "REGISTER", 8 };

   ast_pjproject_get_buildopt("PJ_MAX_HOSTNAME", "%d", &pj_max_hostname);
   /* As of pjproject 2.4.5, PJSIP_MAX_URL_SIZE isn't exposed yet but we try anyway. */
   ast_pjproject_get_buildopt("PJSIP_MAX_URL_SIZE", "%d", &pjsip_max_url_size);

   if (ast_sip_register_service(&registrar_module)) {
      return AST_MODULE_LOAD_DECLINE;
   }

   if (pjsip_endpt_add_capability(ast_sip_get_pjsip_endpoint(), NULL, PJSIP_H_ALLOW, NULL, 1, &STR_REGISTER) != PJ_SUCCESS) {
      ast_sip_unregister_service(&registrar_module);
      return AST_MODULE_LOAD_DECLINE;
   }

   ast_manager_register_xml(AMI_SHOW_REGISTRATIONS, EVENT_FLAG_SYSTEM,
             ami_show_registrations);
   ast_manager_register_xml(AMI_SHOW_REGISTRATION_CONTACT_STATUSES, EVENT_FLAG_SYSTEM,
             ami_show_registration_contact_statuses);

   ast_sorcery_observer_add(ast_sip_get_sorcery(), "global", &expiration_global_observer);
   ast_sorcery_reload_object(ast_sip_get_sorcery(), "global");

   return AST_MODULE_LOAD_SUCCESS;
}

static int unload_module(void)
{
   if (check_thread != AST_PTHREADT_NULL) {
      check_interval = 0;
      pthread_kill(check_thread, SIGURG);
      pthread_join(check_thread, NULL);

      check_thread = AST_PTHREADT_NULL;
   }

   ast_sorcery_observer_remove(ast_sip_get_sorcery(), "global", &expiration_global_observer);

   ast_manager_unregister(AMI_SHOW_REGISTRATIONS);
   ast_manager_unregister(AMI_SHOW_REGISTRATION_CONTACT_STATUSES);
   ast_sip_unregister_service(&registrar_module);
   ast_sip_transport_monitor_unregister_all(register_contact_transport_shutdown_cb, NULL, NULL);
   return 0;
}

AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "PJSIP Registrar Support",
   .support_level = AST_MODULE_SUPPORT_CORE,
   .load = load_module,
   .unload = unload_module,
   .load_pri = AST_MODPRI_CHANNEL_DEPEND - 3,
   .requires = "res_pjproject,res_pjsip",
);