res_pjsip_outbound_registration.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_pjsip</depend>
   <use type="module">res_statsd</use>
   <support_level>core</support_level>
 ***/

#include "asterisk.h"

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

#include "asterisk/res_pjsip.h"
#include "asterisk/res_pjsip_cli.h"
#include "asterisk/module.h"
#include "asterisk/taskprocessor.h"
#include "asterisk/cli.h"
#include "asterisk/stasis_system.h"
#include "asterisk/threadstorage.h"
#include "asterisk/threadpool.h"
#include "asterisk/statsd.h"
#include "res_pjsip/include/res_pjsip_private.h"
#include "asterisk/vector.h"
#include "asterisk/pbx.h"

/*** DOCUMENTATION
   <configInfo name="res_pjsip_outbound_registration" language="en_US">
      <synopsis>SIP resource for outbound registrations</synopsis>
      <description><para>
         <emphasis>Outbound Registration</emphasis>
         </para>
         <para>This module allows <literal>res_pjsip</literal> to register to other SIP servers.</para>
      </description>
      <configFile name="pjsip.conf">
         <configObject name="registration">
            <synopsis>The configuration for outbound registration</synopsis>
            <description><para>
               Registration is <emphasis>COMPLETELY</emphasis> separate from the rest of
               <literal>pjsip.conf</literal>. A minimal configuration consists of
               setting a <literal>server_uri</literal>   and a <literal>client_uri</literal>.
            </para></description>
            <configOption name="auth_rejection_permanent" default="yes">
               <synopsis>Determines whether failed authentication challenges are treated
               as permanent failures.</synopsis>
               <description><para>If this option is enabled and an authentication challenge fails,
               registration will not be attempted again until the configuration is reloaded.</para></description>
            </configOption>
            <configOption name="client_uri">
               <synopsis>Client SIP URI used when attemping outbound registration</synopsis>
               <description><para>
                  This is the address-of-record for the outbound registration (i.e. the URI in
                  the To header of the REGISTER).</para>
                  <para>For registration with an ITSP, the client SIP URI may need to consist of
                  an account name or number and the provider's hostname for their registrar, e.g.
                  [email protected]. This may differ between providers.</para>
                  <para>For registration to generic registrars, the client SIP URI will depend
                  on networking specifics and configuration of the registrar.
               </para></description>
            </configOption>
            <configOption name="contact_user">
               <synopsis>Contact User to use in request</synopsis>
            </configOption>
            <configOption name="contact_header_params">
               <synopsis>Header parameters to place in the Contact header</synopsis>
            </configOption>
            <configOption name="expiration" default="3600">
               <synopsis>Expiration time for registrations in seconds</synopsis>
            </configOption>
            <configOption name="max_retries" default="10">
               <synopsis>Maximum number of registration attempts.</synopsis>
               <description><para>
                  This sets the maximum number of registration attempts that are made before
                  stopping any further attempts. If set to 0 then upon failure no further attempts
                  are made.
               </para></description>
            </configOption>
            <configOption name="outbound_auth" default="">
               <synopsis>Authentication object(s) to be used for outbound registrations.</synopsis>
               <description><para>
                  This is a comma-delimited list of <replaceable>auth</replaceable>
                  sections defined in <filename>pjsip.conf</filename> used to respond
                  to outbound authentication challenges.</para>
                  <note><para>
                  Using the same auth section for inbound and outbound
                  authentication is not recommended.  There is a difference in
                  meaning for an empty realm setting between inbound and outbound
                  authentication uses.  See the auth realm description for details.
                  </para></note>
               </description>
            </configOption>
            <configOption name="outbound_proxy" default="">
               <synopsis>Full SIP URI of the outbound proxy used to send registrations</synopsis>
            </configOption>
            <configOption name="retry_interval" default="60">
               <synopsis>Interval in seconds between retries if outbound registration is unsuccessful</synopsis>
            </configOption>
            <configOption name="forbidden_retry_interval" default="0">
               <synopsis>Interval used when receiving a 403 Forbidden response.</synopsis>
               <description><para>
                  If a 403 Forbidden is received, chan_pjsip will wait
                  <replaceable>forbidden_retry_interval</replaceable> seconds before
                  attempting registration again. If 0 is specified, chan_pjsip will not
                  retry after receiving a 403 Forbidden response. Setting this to a non-zero
                  value goes against a "SHOULD NOT" in RFC3261, but can be used to work around
                  buggy registrars.
               </para></description>
            </configOption>
            <configOption name="fatal_retry_interval" default="0">
               <synopsis>Interval used when receiving a Fatal response.</synopsis>
               <description><para>
                  If a fatal response is received, chan_pjsip will wait
                  <replaceable>fatal_retry_interval</replaceable> seconds before
                  attempting registration again. If 0 is specified, chan_pjsip will not
                  retry after receiving a fatal (non-temporary 4xx, 5xx, 6xx) response.
                  Setting this to a non-zero value may go against a "SHOULD NOT" in RFC3261,
                  but can be used to work around buggy registrars.</para>
                  <note><para>if also set the <replaceable>forbidden_retry_interval</replaceable>
                  takes precedence over this one when a 403 is received.
                  Also, if <replaceable>auth_rejection_permanent</replaceable> equals 'yes' then
                  a 401 and 407 become subject to this retry interval.</para></note>
               </description>
            </configOption>
            <configOption name="server_uri">
               <synopsis>SIP URI of the server to register against</synopsis>
               <description><para>
                  This is the URI at which to find the registrar to send the outbound REGISTER. This URI
                  is used as the request URI of the outbound REGISTER request from Asterisk.</para>
                  <para>For registration with an ITSP, the setting may often be just the domain of
                  the registrar, e.g. sip:sip.example.com.
               </para></description>
            </configOption>
            <configOption name="transport">
               <synopsis>Transport used for outbound authentication</synopsis>
               <description>
                  <note><para>A <replaceable>transport</replaceable> configured in
                  <literal>pjsip.conf</literal>. As with other <literal>res_pjsip</literal> modules, this will use the first available transport of the appropriate type if unconfigured.</para></note>
               </description>
            </configOption>
            <configOption name="line">
               <synopsis>Whether to add a 'line' parameter to the Contact for inbound call matching</synopsis>
               <description><para>
                  When enabled this option will cause a 'line' parameter to be added to the Contact
                  header placed into the outgoing registration request. If the remote server sends a call
                  this line parameter will be used to establish a relationship to the outbound registration,
                  ultimately causing the configured endpoint to be used.
               </para></description>
            </configOption>
            <configOption name="endpoint">
               <synopsis>Endpoint to use for incoming related calls</synopsis>
               <description><para>
                  When line support is enabled this configured endpoint name is used for incoming calls
                  that are related to the outbound registration.
               </para></description>
            </configOption>
            <configOption name="type">
               <synopsis>Must be of type 'registration'.</synopsis>
            </configOption>
            <configOption name="support_path">
               <synopsis>Enables advertising SIP Path support for outbound REGISTER requests.</synopsis>
               <description><para>
                  When this option is enabled, outbound REGISTER requests will advertise
                  support for Path headers so that intervening proxies can add to the Path
                  header as necessary.
               </para></description>
            </configOption>
            <configOption name="support_outbound">
               <synopsis>Enables advertising SIP Outbound support (RFC5626) for outbound REGISTER requests.</synopsis>
            </configOption>
         </configObject>
      </configFile>
   </configInfo>
   <manager name="PJSIPUnregister" language="en_US">
      <synopsis>
         Unregister an outbound registration.
      </synopsis>
      <syntax>
         <xi:include xpointer="xpointer(/docs/manager[@name='Login']/syntax/parameter[@name='ActionID'])" />
         <parameter name="Registration" required="true">
            <para>The outbound registration to unregister or '*all' to unregister them all.</para>
         </parameter>
      </syntax>
      <description>
         <para>
         Unregisters the specified (or all) outbound registration(s) and stops future registration attempts.
         Call PJSIPRegister to start registration and schedule re-registrations according to configuration.
            </para>
      </description>
   </manager>
   <manager name="PJSIPRegister" language="en_US">
      <synopsis>
         Register an outbound registration.
      </synopsis>
      <syntax>
         <xi:include xpointer="xpointer(/docs/manager[@name='Login']/syntax/parameter[@name='ActionID'])" />
         <parameter name="Registration" required="true">
            <para>The outbound registration to register or '*all' to register them all.</para>
         </parameter>
      </syntax>
      <description>
         <para>
         Unregisters the specified (or all) outbound registration(s) then starts registration and schedules re-registrations
         according to configuration.
            </para>
      </description>
   </manager>
   <manager name="PJSIPShowRegistrationsOutbound" language="en_US">
      <synopsis>
         Lists PJSIP outbound registrations.
      </synopsis>
      <syntax />
      <description>
         <para>
         In response <literal>OutboundRegistrationDetail</literal> events showing configuration and status
         information are raised for each outbound registration object. <literal>AuthDetail</literal>
         events are raised for each associated auth object as well.  Once all events are completed an
         <literal>OutboundRegistrationDetailComplete</literal> is issued.
                        </para>
      </description>
   </manager>
 ***/

/* forward declarations */
static int set_outbound_initial_authentication_credentials(pjsip_regc *regc,
      const struct ast_sip_auth_vector *auth_vector);

/*! \brief Some thread local storage used to determine if the running thread invoked the callback */
AST_THREADSTORAGE(register_callback_invoked);

/*! \brief Amount of buffer time (in seconds) before expiration that we re-register at */
#define REREGISTER_BUFFER_TIME 10

/*! \brief Size of the buffer for creating a unique string for the line */
#define LINE_PARAMETER_SIZE 8

/*! \brief Various states that an outbound registration may be in */
enum sip_outbound_registration_status {
   /*! \brief Currently unregistered */
   SIP_REGISTRATION_UNREGISTERED = 0,
   /*! \brief Registered, yay! */
   SIP_REGISTRATION_REGISTERED,
   /*! \brief Registration was rejected, but response was temporal */
   SIP_REGISTRATION_REJECTED_TEMPORARY,
   /*! \brief Registration was rejected, permanently */
   SIP_REGISTRATION_REJECTED_PERMANENT,
   /*! \brief Registration is stopping. */
   SIP_REGISTRATION_STOPPING,
   /*! \brief Registration has been stopped */
   SIP_REGISTRATION_STOPPED,
};

/*!
 * \internal
 * \brief Convert the internal registration state to an external status string.
 * \since 13.5.0
 *
 * \param state Current outbound registration state.
 *
 * \return External registration status string.
 */
static const char *sip_outbound_registration_status_str(enum sip_outbound_registration_status state)
{
   const char *str;

   str = "Unregistered";
   switch (state) {
   case SIP_REGISTRATION_STOPPING:
   case SIP_REGISTRATION_STOPPED:
   case SIP_REGISTRATION_UNREGISTERED:
      break;
   case SIP_REGISTRATION_REGISTERED:
      str = "Registered";
      break;
   case SIP_REGISTRATION_REJECTED_TEMPORARY:
   case SIP_REGISTRATION_REJECTED_PERMANENT:
      str = "Rejected";
      break;
   }
   return str;
}

/*! \brief Outbound registration information */
struct sip_outbound_registration {
   /*! \brief Sorcery object details */
   SORCERY_OBJECT(details);
   /*! \brief Stringfields */
   AST_DECLARE_STRING_FIELDS(
      /*! \brief URI for the registrar */
      AST_STRING_FIELD(server_uri);
      /*! \brief URI for the AOR */
      AST_STRING_FIELD(client_uri);
      /*! \brief Optional user for contact header */
      AST_STRING_FIELD(contact_user);
      /*! \bried Optional header parameters for contact */
      AST_STRING_FIELD(contact_header_params);
      /*! \brief Explicit transport to use for registration */
      AST_STRING_FIELD(transport);
      /*! \brief Outbound proxy to use */
      AST_STRING_FIELD(outbound_proxy);
      /*! \brief Endpoint to use for related incoming calls */
      AST_STRING_FIELD(endpoint);
   );
   /*! \brief Requested expiration time */
   unsigned int expiration;
   /*! \brief Interval at which retries should occur for temporal responses */
   unsigned int retry_interval;
   /*! \brief Interval at which retries should occur for permanent responses */
   unsigned int forbidden_retry_interval;
   /*! \brief Interval at which retries should occur for all permanent responses */
   unsigned int fatal_retry_interval;
   /*! \brief Treat authentication challenges that we cannot handle as permanent failures */
   unsigned int auth_rejection_permanent;
   /*! \brief Maximum number of retries permitted */
   unsigned int max_retries;
   /*! \brief Whether to add a line parameter to the outbound Contact or not */
   unsigned int line;
   /*! \brief Configured authentication credentials */
   struct ast_sip_auth_vector outbound_auths;
   /*! \brief Whether Path support is enabled */
   unsigned int support_path;
   /*! \brief Whether Outbound support is enabled */
   unsigned int support_outbound;
};

/*! \brief Outbound registration client state information (persists for lifetime of regc) */
struct sip_outbound_registration_client_state {
   /*! \brief Current state of this registration */
   enum sip_outbound_registration_status status;
   /*!
    * \brief Outbound registration client
    * \note May only be accessed within the serializer thread
    * because it might get destroyed and set to NULL for
    * module unload.
    */
   pjsip_regc *client;
   /*!
    * \brief Last tdata sent
    * We need the original tdata to resend a request on auth failure
    * or timeout.  On an auth failure, we use the original tdata
    * to initialize the new tdata for the authorized response.  On a timeout
    * we need it to skip failed SRV entries if any.
    */
   pjsip_tx_data *last_tdata;
   /*! \brief Timer entry for retrying on temporal responses */
   pj_timer_entry timer;
   /*! \brief Optional line parameter placed into Contact */
   char line[LINE_PARAMETER_SIZE];
   /*! \brief Current number of retries */
   unsigned int retries;
   /*! \brief Maximum number of retries permitted */
   unsigned int max_retries;
   /*! \brief Interval at which retries should occur for temporal responses */
   unsigned int retry_interval;
   /*! \brief Interval at which retries should occur for permanent responses */
   unsigned int forbidden_retry_interval;
   /*! \brief Interval at which retries should occur for all permanent responses */
   unsigned int fatal_retry_interval;
   /*! \brief Treat authentication challenges that we cannot handle as permanent failures */
   unsigned int auth_rejection_permanent;
   /*! \brief Determines whether SIP Path support should be advertised */
   unsigned int support_path;
   /*! \brief Determines whether SIP Outbound support should be advertised */
   unsigned int support_outbound;
   /*! CSeq number of last sent auth request. */
   unsigned int auth_cseq;
   /*! \brief Serializer for stuff and things */
   struct ast_taskprocessor *serializer;
   /*! \brief Configured authentication credentials */
   struct ast_sip_auth_vector outbound_auths;
   /*! \brief Registration should be destroyed after completion of transaction */
   unsigned int destroy:1;
   /*! \brief Non-zero if we have attempted sending a REGISTER with authentication */
   unsigned int auth_attempted:1;
   /*! \brief The name of the transport to be used for the registration */
   char *transport_name;
   /*! \brief The name of the registration sorcery object */
   char *registration_name;
};

/*! \brief Outbound registration state information (persists for lifetime that registration should exist) */
struct sip_outbound_registration_state {
   /*! \brief Outbound registration configuration object */
   struct sip_outbound_registration *registration;
   /*! \brief Client state information */
   struct sip_outbound_registration_client_state *client_state;
};

/*! Time needs to be long enough for a transaction to timeout if nothing replies. */
#define MAX_UNLOAD_TIMEOUT_TIME     35 /* Seconds */

/*! Shutdown group to monitor sip_outbound_registration_client_state serializers. */
static struct ast_serializer_shutdown_group *shutdown_group;

/*! \brief Default number of state container buckets */
#define DEFAULT_STATE_BUCKETS 53
static AO2_GLOBAL_OBJ_STATIC(current_states);

/*! subscription id for network change events */
static struct stasis_subscription *network_change_sub;

/*! \brief hashing function for state objects */
static int registration_state_hash(const void *obj, const int flags)
{
   const struct sip_outbound_registration_state *object;
   const char *key;

   switch (flags & OBJ_SEARCH_MASK) {
   case OBJ_SEARCH_KEY:
      key = obj;
      break;
   case OBJ_SEARCH_OBJECT:
      object = obj;
      key = ast_sorcery_object_get_id(object->registration);
      break;
   default:
      ast_assert(0);
      return 0;
   }
   return ast_str_hash(key);
}

/*! \brief comparator function for state objects */
static int registration_state_cmp(void *obj, void *arg, int flags)
{
   const struct sip_outbound_registration_state *object_left = obj;
   const struct sip_outbound_registration_state *object_right = arg;
   const char *right_key = arg;
   int cmp;

   switch (flags & OBJ_SEARCH_MASK) {
   case OBJ_SEARCH_OBJECT:
      right_key = ast_sorcery_object_get_id(object_right->registration);
      /* Fall through */
   case OBJ_SEARCH_KEY:
      cmp = strcmp(ast_sorcery_object_get_id(object_left->registration), right_key);
      break;
   case OBJ_SEARCH_PARTIAL_KEY:
      /* Not supported by container. */
      ast_assert(0);
      return 0;
   default:
      cmp = 0;
      break;
   }
   if (cmp) {
      return 0;
   }
   return CMP_MATCH;
}

static struct sip_outbound_registration_state *get_state(const char *id)
{
   struct sip_outbound_registration_state *state = NULL;
   struct ao2_container *states;

   states = ao2_global_obj_ref(current_states);
   if (states) {
      state = ao2_find(states, id, OBJ_SEARCH_KEY);
      ao2_ref(states, -1);
   }
   return state;
}

static struct ao2_container *get_registrations(void)
{
   struct ao2_container *registrations = ast_sorcery_retrieve_by_fields(
      ast_sip_get_sorcery(), "registration",
      AST_RETRIEVE_FLAG_MULTIPLE | AST_RETRIEVE_FLAG_ALL, NULL);

   return registrations;
}

/*! \brief Callback function for matching an outbound registration based on line */
static int line_identify_relationship(void *obj, void *arg, int flags)
{
   struct sip_outbound_registration_state *state = obj;
   pjsip_param *line = arg;

   return !pj_strcmp2(&line->value, state->client_state->line) ? CMP_MATCH : 0;
}

static struct pjsip_param *get_uri_option_line(const void *uri)
{
   pjsip_sip_uri *pjuri;
   static const pj_str_t LINE_STR = { "line", 4 };

   if (!PJSIP_URI_SCHEME_IS_SIP(uri) && !PJSIP_URI_SCHEME_IS_SIPS(uri)) {
      return NULL;
   }
   pjuri = pjsip_uri_get_uri(uri);
   return pjsip_param_find(&pjuri->other_param, &LINE_STR);
}

/*! \brief Endpoint identifier which uses the 'line' parameter to establish a relationship to an outgoing registration */
static struct ast_sip_endpoint *line_identify(pjsip_rx_data *rdata)
{
   pjsip_param *line;
   RAII_VAR(struct ao2_container *, states, NULL, ao2_cleanup);
   RAII_VAR(struct sip_outbound_registration_state *, state, NULL, ao2_cleanup);

   if (!(line = get_uri_option_line(rdata->msg_info.to->uri))
      && !(line = get_uri_option_line(rdata->msg_info.msg->line.req.uri))) {
      return NULL;
   }

   states = ao2_global_obj_ref(current_states);
   if (!states) {
      return NULL;
   }

   state = ao2_callback(states, 0, line_identify_relationship, line);
   if (!state || ast_strlen_zero(state->registration->endpoint)) {
      return NULL;
   }

   ast_debug(3, "Determined relationship to outbound registration '%s' based on line '%s', using configured endpoint '%s'\n",
      ast_sorcery_object_get_id(state->registration), state->client_state->line, state->registration->endpoint);

   return ast_sorcery_retrieve_by_id(ast_sip_get_sorcery(), "endpoint", state->registration->endpoint);
}

static struct ast_sip_endpoint_identifier line_identifier = {
   .identify_endpoint = line_identify,
};

/*! \brief Helper function which cancels the timer on a client */
static void cancel_registration(struct sip_outbound_registration_client_state *client_state)
{
   if (pj_timer_heap_cancel_if_active(pjsip_endpt_get_timer_heap(ast_sip_get_pjsip_endpoint()),
      &client_state->timer, client_state->timer.id)) {
      /* The timer was successfully cancelled, drop the refcount of client_state */
      ao2_ref(client_state, -1);
   }
}

static pj_str_t PATH_NAME = { "path", 4 };
static pj_str_t OUTBOUND_NAME = { "outbound", 8 };

/*! \brief Helper function which sends a message and cleans up, if needed, on failure */
static pj_status_t registration_client_send(struct sip_outbound_registration_client_state *client_state,
   pjsip_tx_data *tdata)
{
   pj_status_t status;
   int *callback_invoked;
   pjsip_tpselector selector = { .type = PJSIP_TPSELECTOR_NONE, };

   callback_invoked = ast_threadstorage_get(&register_callback_invoked, sizeof(int));
   if (!callback_invoked) {
      pjsip_tx_data_dec_ref(tdata);
      return PJ_ENOMEM;
   }
   *callback_invoked = 0;

   /* Due to the message going out the callback may now be invoked, so bump the count */
   ao2_ref(client_state, +1);
   /*
    * We also bump tdata in expectation of saving it to client_state->last_tdata.
    * We have to do it BEFORE pjsip_regc_send because if it succeeds, it decrements
    * the ref count on its own.
    */
   pjsip_tx_data_add_ref(tdata);

   /*
    * Set the transport in case transports were reloaded.
    * When pjproject removes the extraneous error messages produced,
    * we can check status and only set the transport and resend if there was an error
    */
   ast_sip_set_tpselector_from_transport_name(client_state->transport_name, &selector);
   pjsip_regc_set_transport(client_state->client, &selector);
   ast_sip_tpselector_unref(&selector);

   status = pjsip_regc_send(client_state->client, tdata);

   /*
    * If the attempt to send the message failed and the callback was not invoked we need to
    * drop the references we just added
    */
   if ((status != PJ_SUCCESS) && !(*callback_invoked)) {
      pjsip_tx_data_dec_ref(tdata);
      ao2_ref(client_state, -1);
      return status;
   }

   /*
    * Decref the old last_data before replacing it.
    * BTW, it's quite possible that last_data == tdata
    * if we're trying successive servers in an SRV set.
    */
   if (client_state->last_tdata) {
      pjsip_tx_data_dec_ref(client_state->last_tdata);
   }
   client_state->last_tdata = tdata;

   return status;
}

/*! \brief Helper function to add string to Supported header */
static int add_to_supported_header(pjsip_tx_data *tdata, pj_str_t *name)
{
   pjsip_supported_hdr *hdr;
   int i;

   hdr = pjsip_msg_find_hdr(tdata->msg, PJSIP_H_SUPPORTED, NULL);
   if (!hdr) {
      /* insert a new Supported header */
      hdr = pjsip_supported_hdr_create(tdata->pool);
      if (!hdr) {
         pjsip_tx_data_dec_ref(tdata);
         return 0;
      }

      pjsip_msg_add_hdr(tdata->msg, (pjsip_hdr *)hdr);
   }

   /* Don't add the value if it's already there */
   for (i = 0; i < hdr->count; ++i) {
      if (pj_stricmp(&hdr->values[i], name) == 0) {
         return 1;
      }
   }

   if (hdr->count >= PJSIP_GENERIC_ARRAY_MAX_COUNT) {
      return 0;
   }

   /* add on to the existing Supported header */
   pj_strassign(&hdr->values[hdr->count++], name);

   return 1;
}

/*! \brief Helper function to add configured supported headers */
static int add_configured_supported_headers(struct sip_outbound_registration_client_state *client_state, pjsip_tx_data *tdata)
{
   if (client_state->support_path) {
      if (!add_to_supported_header(tdata, &PATH_NAME)) {
         return 0;
      }
   }

   if (client_state->support_outbound) {
      if (!add_to_supported_header(tdata, &OUTBOUND_NAME)) {
         return 0;
      }
   }

   return 1;
}

/*! \brief Callback function for registering */
static int handle_client_registration(void *data)
{
   RAII_VAR(struct sip_outbound_registration_client_state *, client_state, data, ao2_cleanup);
   pjsip_tx_data *tdata;

   if (set_outbound_initial_authentication_credentials(client_state->client, &client_state->outbound_auths)) {
      ast_log(LOG_WARNING, "Failed to set initial authentication credentials\n");
   }

   if (client_state->status == SIP_REGISTRATION_STOPPED
      || pjsip_regc_register(client_state->client, PJ_FALSE, &tdata) != PJ_SUCCESS) {
      return 0;
   }

   if (DEBUG_ATLEAST(1)) {
      pjsip_regc_info info;

      pjsip_regc_get_info(client_state->client, &info);
      ast_log(LOG_DEBUG, "Outbound REGISTER attempt %u to '%.*s' with client '%.*s'\n",
         client_state->retries + 1,
         (int) info.server_uri.slen, info.server_uri.ptr,
         (int) info.client_uri.slen, info.client_uri.ptr);
   }

   if (!add_configured_supported_headers(client_state, tdata)) {
      ast_log(LOG_WARNING, "Failed to set supported headers\n");
      return -1;
   }

   registration_client_send(client_state, tdata);

   return 0;
}

/*! \brief Timer callback function, used just for registrations */
static void sip_outbound_registration_timer_cb(pj_timer_heap_t *timer_heap, struct pj_timer_entry *entry)
{
   struct sip_outbound_registration_client_state *client_state = entry->user_data;

   entry->id = 0;

   /*
    * Transfer client_state reference to serializer task so the
    * nominal path will not dec the client_state ref in this
    * pjproject callback thread.
    */
   if (ast_sip_push_task(client_state->serializer, handle_client_registration, client_state)) {
      ast_log(LOG_WARNING, "Scheduled outbound registration could not be executed.\n");
      ao2_ref(client_state, -1);
   }
}

/*! \brief Helper function which sets up the timer to re-register in a specific amount of time */
static void schedule_registration(struct sip_outbound_registration_client_state *client_state, unsigned int seconds)
{
   pj_time_val delay = { .sec = seconds, };
   pjsip_regc_info info;

   cancel_registration(client_state);

   pjsip_regc_get_info(client_state->client, &info);
   ast_debug(1, "Scheduling outbound registration to server '%.*s' from client '%.*s' in %d seconds\n",
         (int) info.server_uri.slen, info.server_uri.ptr,
         (int) info.client_uri.slen, info.client_uri.ptr,
         seconds);

   ao2_ref(client_state, +1);
   if (pjsip_endpt_schedule_timer(ast_sip_get_pjsip_endpoint(), &client_state->timer, &delay) != PJ_SUCCESS) {
      ast_log(LOG_WARNING, "Failed to schedule registration to server '%.*s' from client '%.*s'\n",
            (int) info.server_uri.slen, info.server_uri.ptr,
            (int) info.client_uri.slen, info.client_uri.ptr);
      ao2_ref(client_state, -1);
   }
}

static void update_client_state_status(struct sip_outbound_registration_client_state *client_state, enum sip_outbound_registration_status status)
{
   const char *status_old;
   const char *status_new;

   if (client_state->status == status) {
      /* Status state did not change at all. */
      return;
   }

   status_old = sip_outbound_registration_status_str(client_state->status);
   status_new = sip_outbound_registration_status_str(status);
   client_state->status = status;

   if (!strcmp(status_old, status_new)) {
      /*
       * The internal status state may have changed but the status
       * state we tell the world did not change at all.
       */
      return;
   }

   ast_statsd_log_string_va("PJSIP.registrations.state.%s", AST_STATSD_GAUGE, "-1", 1.0,
      status_old);
   ast_statsd_log_string_va("PJSIP.registrations.state.%s", AST_STATSD_GAUGE, "+1", 1.0,
      status_new);
}

/*! \brief Callback function for unregistering (potentially) and destroying state */
static int handle_client_state_destruction(void *data)
{
   struct sip_outbound_registration_client_state *client_state = data;

   cancel_registration(client_state);

   if (client_state->client) {
      pjsip_regc_info info;
      pjsip_tx_data *tdata;

      pjsip_regc_get_info(client_state->client, &info);

      if (info.is_busy == PJ_TRUE) {
         /* If a client transaction is in progress we defer until it is complete */
         ast_debug(1,
            "Registration transaction is busy with server '%.*s' from client '%.*s'.\n",
            (int) info.server_uri.slen, info.server_uri.ptr,
            (int) info.client_uri.slen, info.client_uri.ptr);
         client_state->destroy = 1;
         ao2_ref(client_state, -1);
         return 0;
      }

      switch (client_state->status) {
      case SIP_REGISTRATION_UNREGISTERED:
         break;
      case SIP_REGISTRATION_REGISTERED:
         ast_debug(1,
            "Trying to unregister with server '%.*s' from client '%.*s' before destruction.\n",
            (int) info.server_uri.slen, info.server_uri.ptr,
            (int) info.client_uri.slen, info.client_uri.ptr);

         update_client_state_status(client_state, SIP_REGISTRATION_STOPPING);
         client_state->destroy = 1;
         if (pjsip_regc_unregister(client_state->client, &tdata) == PJ_SUCCESS
            && add_configured_supported_headers(client_state, tdata)
            && registration_client_send(client_state, tdata) == PJ_SUCCESS) {
            ao2_ref(client_state, -1);
            return 0;
         }
         break;
      case SIP_REGISTRATION_REJECTED_TEMPORARY:
      case SIP_REGISTRATION_REJECTED_PERMANENT:
      case SIP_REGISTRATION_STOPPING:
      case SIP_REGISTRATION_STOPPED:
         break;
      }

      pjsip_regc_destroy(client_state->client);
      client_state->client = NULL;
   }

   update_client_state_status(client_state, SIP_REGISTRATION_STOPPED);
   ast_sip_auth_vector_destroy(&client_state->outbound_auths);
   ao2_ref(client_state, -1);

   return 0;
}

/*! \brief Structure for registration response */
struct registration_response {
   /*! \brief Response code for the registration attempt */
   int code;
   /*! \brief Expiration time for registration */
   int expiration;
   /*! \brief Retry-After value */
   int retry_after;
   /*! \brief Outbound registration client state */
   struct sip_outbound_registration_client_state *client_state;
   /*! \brief The response message */
   pjsip_rx_data *rdata;
   /*! \brief Request for which the response was received */
   pjsip_tx_data *old_request;
};

/*! \brief Registration response structure destructor */
static void registration_response_destroy(void *obj)
{
   struct registration_response *response = obj;

   if (response->rdata) {
      pjsip_rx_data_free_cloned(response->rdata);
   }

   if (response->old_request) {
      pjsip_tx_data_dec_ref(response->old_request);
   }

   ao2_cleanup(response->client_state);
}

/*! \brief Helper function which determines if a response code is temporal or not */
static int sip_outbound_registration_is_temporal(unsigned int code,
      struct sip_outbound_registration_client_state *client_state)
{
   /* Shamelessly taken from pjsua */
   if (code == PJSIP_SC_REQUEST_TIMEOUT ||
      code == PJSIP_SC_INTERNAL_SERVER_ERROR ||
      code == PJSIP_SC_BAD_GATEWAY ||
      code == PJSIP_SC_SERVICE_UNAVAILABLE ||
      code == PJSIP_SC_SERVER_TIMEOUT ||
      ((code == PJSIP_SC_UNAUTHORIZED ||
        code == PJSIP_SC_PROXY_AUTHENTICATION_REQUIRED) &&
       !client_state->auth_rejection_permanent) ||
      PJSIP_IS_STATUS_IN_CLASS(code, 600)) {
      return 1;
   } else {
      return 0;
   }
}

static void schedule_retry(struct registration_response *response, unsigned int interval,
            const char *server_uri, const char *client_uri)
{
   update_client_state_status(response->client_state, SIP_REGISTRATION_REJECTED_TEMPORARY);
   schedule_registration(response->client_state, interval);

   if (response->rdata) {
      ast_log(LOG_WARNING, "Temporal response '%d' received from '%s' on "
         "registration attempt to '%s', retrying in '%u'\n",
         response->code, server_uri, client_uri, interval);
   } else {
      ast_log(LOG_WARNING, "No response received from '%s' on "
         "registration attempt to '%s', retrying in '%u'\n",
         server_uri, client_uri, interval);
   }
}

static int reregister_immediately_cb(void *obj)
{
   struct sip_outbound_registration_state *state = obj;

   if (state->client_state->status != SIP_REGISTRATION_REGISTERED) {
      ao2_ref(state, -1);
      return 0;
   }

   if (DEBUG_ATLEAST(1)) {
      pjsip_regc_info info;

      pjsip_regc_get_info(state->client_state->client, &info);
      ast_log(LOG_DEBUG,
         "Outbound registration transport to server '%.*s' from client '%.*s' shutdown\n",
         (int) info.server_uri.slen, info.server_uri.ptr,
         (int) info.client_uri.slen, info.client_uri.ptr);
   }

   cancel_registration(state->client_state);

   ao2_ref(state->client_state, +1);
   handle_client_registration(state->client_state);

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

/*!
 * \internal
 * \brief The reliable transport we registered using has shutdown.
 * \since 13.18.0
 *
 * \param obj What is needed to initiate a reregister attempt.
 *
 * \note Normally executed by the pjsip monitor thread.
 *
 * \return Nothing
 */
static void registration_transport_shutdown_cb(void *obj)
{
   const char *registration_name = obj;
   struct sip_outbound_registration_state *state;

   state = get_state(registration_name);
   if (!state) {
      /* Registration no longer exists or shutting down. */
      return;
   }
   if (ast_sip_push_task(state->client_state->serializer, reregister_immediately_cb, state)) {
      ao2_ref(state, -1);
   }
}

static int monitor_matcher(void *a, void *b)
{
   char *ma = a;
   char *mb = b;

   return strcmp(ma, mb) == 0;
}

static void registration_transport_monitor_setup(pjsip_transport *transport, const char *registration_name)
{
   char *monitor;

   if (!PJSIP_TRANSPORT_IS_RELIABLE(transport)) {
      return;
   }
   monitor = ao2_alloc_options(strlen(registration_name) + 1, NULL,
      AO2_ALLOC_OPT_LOCK_NOLOCK);
   if (!monitor) {
      return;
   }
   strcpy(monitor, registration_name);/* Safe */

   /*
    * We'll ignore if the transport has already been shutdown before we
    * register the monitor.  We might get into a message spamming infinite
    * loop of registration, shutdown, reregistration...
    */
   ast_sip_transport_monitor_register(transport, registration_transport_shutdown_cb,
      monitor);
   ao2_ref(monitor, -1);
}

static void save_response_fields_to_transport(struct registration_response *response)
{
   static const pj_str_t associated_uri_str = { "P-Associated-URI", 16 };
   static const pj_str_t service_route_str = { "Service-Route", 13 };
   pjsip_hdr *header = NULL;
   pjsip_msg *msg = response->rdata->msg_info.msg;
   struct ast_sip_service_route_vector *service_routes = NULL;

   /* If no transport is specified then we can't update any */
   if (ast_strlen_zero(response->client_state->transport_name)) {
      return;
   }

   ast_sip_transport_state_set_transport(response->client_state->transport_name, response->rdata->tp_info.transport);

   while ((header = pjsip_msg_find_hdr_by_name(msg, &service_route_str, header ? header->next : NULL))) {
      char *service_route;
      size_t size;

      /* The below code takes the approach that if we can't store all service routes then we
       * store none at all. This gives a predictable failure condition instead of storing a
       * partial list and having partial route headers.
       */
      size = pj_strlen(&((pjsip_generic_string_hdr*)header)->hvalue) + 1;
      service_route = ast_malloc(size);
      if (!service_route) {
         if (service_routes) {
            ast_sip_service_route_vector_destroy(service_routes);
            service_routes = NULL;
         }
         break;
      }

      ast_copy_pj_str(service_route, &((pjsip_generic_string_hdr*)header)->hvalue, size);

      if (!service_routes) {
         service_routes = ast_sip_service_route_vector_alloc();
         if (!service_routes) {
            ast_free(service_route);
            break;
         }
      }

      if (AST_VECTOR_APPEND(service_routes, service_route)) {
         ast_free(service_route);
         ast_sip_service_route_vector_destroy(service_routes);
         service_routes = NULL;
         break;
      }
   }

   /* If any service routes were handled then store them on the transport */
   if (service_routes) {
      ast_sip_transport_state_set_service_routes(response->client_state->transport_name, service_routes);
   }

   /* If an associated URI is present in the response we need to use it on any outgoing
    * traffic on the transport.
    */
   header = pjsip_msg_find_hdr_by_name(msg, &associated_uri_str, NULL);
   if (header) {
      char value[pj_strlen(&((pjsip_generic_string_hdr*)header)->hvalue) + 1];

      ast_copy_pj_str(value, &((pjsip_generic_string_hdr*)header)->hvalue, sizeof(value));
      ast_sip_transport_state_set_preferred_identity(response->client_state->transport_name, value);
   }
}


/*! \brief Callback function for handling a response to a registration attempt */
static int handle_registration_response(void *data)
{
   struct registration_response *response = data;
   pjsip_regc_info info;
   char server_uri[PJSIP_MAX_URL_SIZE];
   char client_uri[PJSIP_MAX_URL_SIZE];

   if (response->client_state->status == SIP_REGISTRATION_STOPPED) {
      ao2_ref(response, -1);
      return 0;
   }

   pjsip_regc_get_info(response->client_state->client, &info);
   ast_copy_pj_str(server_uri, &info.server_uri, sizeof(server_uri));
   ast_copy_pj_str(client_uri, &info.client_uri, sizeof(client_uri));

   ast_debug(1, "Processing REGISTER response %d from server '%s' for client '%s'\n",
         response->code, server_uri, client_uri);

   if (response->code == 408 || response->code == 503) {
      if ((ast_sip_failover_request(response->old_request))) {
         int res = registration_client_send(response->client_state, response->old_request);
         /* The tdata ref was stolen */
         response->old_request = NULL;
         if (res == PJ_SUCCESS) {
            ao2_ref(response, -1);
            return 0;
         }
      }
   } else if ((response->code == 401 || response->code == 407)
      && (!response->client_state->auth_attempted
         || response->rdata->msg_info.cseq->cseq != response->client_state->auth_cseq)) {
      int res;
      pjsip_cseq_hdr *cseq_hdr;
      pjsip_tx_data *tdata;

      if (!ast_sip_create_request_with_auth(&response->client_state->outbound_auths,
            response->rdata, response->old_request, &tdata)) {
         response->client_state->auth_attempted = 1;
         ast_debug(1, "Sending authenticated REGISTER to server '%s' from client '%s'\n",
               server_uri, client_uri);
         pjsip_tx_data_add_ref(tdata);
         res = registration_client_send(response->client_state, tdata);

         /* Save the cseq that actually got sent. */
         cseq_hdr = (pjsip_cseq_hdr *) pjsip_msg_find_hdr(tdata->msg, PJSIP_H_CSEQ,
            NULL);
         response->client_state->auth_cseq = cseq_hdr->cseq;
         pjsip_tx_data_dec_ref(tdata);
         if (res == PJ_SUCCESS) {
            ao2_ref(response, -1);
            return 0;
         }
      } else {
         ast_log(LOG_WARNING, "Failed to create authenticated REGISTER request to server '%s' from client '%s'\n",
               server_uri, client_uri);
      }
      /* Otherwise, fall through so the failure is processed appropriately */
   }

   response->client_state->auth_attempted = 0;

   if (PJSIP_IS_STATUS_IN_CLASS(response->code, 200)) {
      /* Check if this is in regards to registering or unregistering */
      if (response->expiration) {
         int next_registration_round;

         /* If the registration went fine simply reschedule registration for the future */
         ast_debug(1, "Outbound registration to '%s' with client '%s' successful\n", server_uri, client_uri);
         update_client_state_status(response->client_state, SIP_REGISTRATION_REGISTERED);
         response->client_state->retries = 0;
         next_registration_round = response->expiration - REREGISTER_BUFFER_TIME;
         if (next_registration_round < 0) {
            /* Re-register immediately. */
            next_registration_round = 0;
         }
         schedule_registration(response->client_state, next_registration_round);

         /* See if we should monitor for transport shutdown */
         registration_transport_monitor_setup(response->rdata->tp_info.transport,
            response->client_state->registration_name);
      } else {
         ast_debug(1, "Outbound unregistration to '%s' with client '%s' successful\n", server_uri, client_uri);
         update_client_state_status(response->client_state, SIP_REGISTRATION_UNREGISTERED);
         ast_sip_transport_monitor_unregister(response->rdata->tp_info.transport,
            registration_transport_shutdown_cb, response->client_state->registration_name,
            monitor_matcher);
      }

      save_response_fields_to_transport(response);
   } else if (response->client_state->destroy) {
      /* We need to deal with the pending destruction instead. */
   } else if (response->retry_after) {
      /* If we have been instructed to retry after a period of time, schedule it as such */
      schedule_retry(response, response->retry_after, server_uri, client_uri);
   } else if (response->client_state->retry_interval
      && sip_outbound_registration_is_temporal(response->code, response->client_state)) {
      if (response->client_state->retries == response->client_state->max_retries) {
         /* If we received enough temporal responses to exceed our maximum give up permanently */
         update_client_state_status(response->client_state, SIP_REGISTRATION_REJECTED_PERMANENT);
         ast_log(LOG_WARNING, "Maximum retries reached when attempting outbound registration to '%s' with client '%s', stopping registration attempt\n",
            server_uri, client_uri);
      } else {
         /* On the other hand if we can still try some more do so */
         response->client_state->retries++;
         schedule_retry(response, response->client_state->retry_interval, server_uri, client_uri);
      }
   } else {
      if (response->code == 403
         && response->client_state->forbidden_retry_interval
         && response->client_state->retries < response->client_state->max_retries) {
         /* A forbidden response retry interval is configured and there are retries remaining */
         update_client_state_status(response->client_state, SIP_REGISTRATION_REJECTED_TEMPORARY);
         response->client_state->retries++;
         schedule_registration(response->client_state, response->client_state->forbidden_retry_interval);
         ast_log(LOG_WARNING, "403 Forbidden fatal response received from '%s' on registration attempt to '%s', retrying in '%u' seconds\n",
            server_uri, client_uri, response->client_state->forbidden_retry_interval);
      } else if (response->client_state->fatal_retry_interval
            && response->client_state->retries < response->client_state->max_retries) {
         /* Some kind of fatal failure response received, so retry according to configured interval */
         update_client_state_status(response->client_state, SIP_REGISTRATION_REJECTED_TEMPORARY);
         response->client_state->retries++;
         schedule_registration(response->client_state, response->client_state->fatal_retry_interval);
         ast_log(LOG_WARNING, "'%d' fatal response received from '%s' on registration attempt to '%s', retrying in '%u' seconds\n",
            response->code, server_uri, client_uri, response->client_state->fatal_retry_interval);
      } else {
         /* Finally if there's no hope of registering give up */
         update_client_state_status(response->client_state, SIP_REGISTRATION_REJECTED_PERMANENT);
         if (response->rdata) {
            ast_log(LOG_WARNING, "Fatal response '%d' received from '%s' on registration attempt to '%s', stopping outbound registration\n",
               response->code, server_uri, client_uri);
         } else {
            ast_log(LOG_WARNING, "Fatal registration attempt to '%s', stopping outbound registration\n", client_uri);
         }
      }
   }

   ast_system_publish_registry("PJSIP", client_uri, server_uri,
      sip_outbound_registration_status_str(response->client_state->status), NULL);

   if (response->client_state->destroy) {
      /* We have a pending deferred destruction to complete now. */
      ao2_ref(response->client_state, +1);
      handle_client_state_destruction(response->client_state);
   }

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

/*! \brief Callback function for outbound registration client */
static void sip_outbound_registration_response_cb(struct pjsip_regc_cbparam *param)
{
   struct sip_outbound_registration_client_state *client_state = param->token;
   struct registration_response *response;
   int *callback_invoked;

   callback_invoked = ast_threadstorage_get(&register_callback_invoked, sizeof(int));

   ast_assert(callback_invoked != NULL);
   ast_assert(client_state != NULL);

   *callback_invoked = 1;

   response = ao2_alloc(sizeof(*response), registration_response_destroy);
   if (!response) {
      ao2_ref(client_state, -1);
      return;
   }
   response->code = param->code;
   response->expiration = param->expiration;
   /*
    * Transfer client_state reference to response so the
    * nominal path will not dec the client_state ref in this
    * pjproject callback thread.
    */
   response->client_state = client_state;

   ast_debug(1, "Received REGISTER response %d(%.*s)\n",
      param->code, (int) param->reason.slen, param->reason.ptr);

   if (param->rdata) {
      struct pjsip_retry_after_hdr *retry_after;
      pjsip_transaction *tsx;

      retry_after = pjsip_msg_find_hdr(param->rdata->msg_info.msg, PJSIP_H_RETRY_AFTER,
         NULL);
      response->retry_after = retry_after ? retry_after->ivalue : 0;

      /*
       * If we got a response from the server, we have to use the tdata
       * from the transaction, not the tdata saved when we sent the
       * request.  If we use the saved tdata, we won't process responses
       * like 423 Interval Too Brief correctly and we'll wind up sending
       * the bad Expires value again.
       */
      pjsip_tx_data_dec_ref(client_state->last_tdata);

      tsx = pjsip_rdata_get_tsx(param->rdata);
      response->old_request = tsx->last_tx;
      pjsip_tx_data_add_ref(response->old_request);
      pjsip_rx_data_clone(param->rdata, 0, &response->rdata);
   } else {
      /* old_request steals the reference */
      response->old_request = client_state->last_tdata;
   }
   client_state->last_tdata = NULL;

   /*
    * Transfer response reference to serializer task so the
    * nominal path will not dec the response ref in this
    * pjproject callback thread.
    */
   if (ast_sip_push_task(client_state->serializer, handle_registration_response, response)) {
      ast_log(LOG_WARNING, "Failed to pass incoming registration response to threadpool\n");
      ao2_cleanup(response);
   }
}

/*! \brief Destructor function for registration state */
static void sip_outbound_registration_state_destroy(void *obj)
{
   struct sip_outbound_registration_state *state = obj;

   ast_debug(3, "Destroying registration state for registration to server '%s' from client '%s'\n",
      state->registration ? state->registration->server_uri : "",
      state->registration ? state->registration->client_uri : "");
   ao2_cleanup(state->registration);

   if (!state->client_state) {
      /* Nothing to do */
   } else if (!state->client_state->serializer) {
      ao2_ref(state->client_state, -1);
   } else if (ast_sip_push_task(state->client_state->serializer,
      handle_client_state_destruction, state->client_state)) {
      ast_log(LOG_WARNING, "Failed to pass outbound registration client destruction to threadpool\n");
      ao2_ref(state->client_state, -1);
   }
}

/*! \brief Destructor function for client registration state */
static void sip_outbound_registration_client_state_destroy(void *obj)
{
   struct sip_outbound_registration_client_state *client_state = obj;

   ast_statsd_log_string("PJSIP.registrations.count", AST_STATSD_GAUGE, "-1", 1.0);
   ast_statsd_log_string_va("PJSIP.registrations.state.%s", AST_STATSD_GAUGE, "-1", 1.0,
      sip_outbound_registration_status_str(client_state->status));

   ast_taskprocessor_unreference(client_state->serializer);
   ast_free(client_state->transport_name);
   ast_free(client_state->registration_name);
   if (client_state->last_tdata) {
      pjsip_tx_data_dec_ref(client_state->last_tdata);
   }
}

/*! \brief Allocator function for registration state */
static struct sip_outbound_registration_state *sip_outbound_registration_state_alloc(struct sip_outbound_registration *registration)
{
   struct sip_outbound_registration_state *state;
   char tps_name[AST_TASKPROCESSOR_MAX_NAME + 1];

   state = ao2_alloc(sizeof(*state), sip_outbound_registration_state_destroy);
   if (!state) {
      return NULL;
   }
   state->client_state = ao2_alloc(sizeof(*state->client_state),
      sip_outbound_registration_client_state_destroy);
   if (!state->client_state) {
      ao2_cleanup(state);
      return NULL;
   }

   state->client_state->status = SIP_REGISTRATION_UNREGISTERED;
   pj_timer_entry_init(&state->client_state->timer, 0, state->client_state,
      sip_outbound_registration_timer_cb);
   state->client_state->transport_name = ast_strdup(registration->transport);
   state->client_state->registration_name =
      ast_strdup(ast_sorcery_object_get_id(registration));

   ast_statsd_log_string("PJSIP.registrations.count", AST_STATSD_GAUGE, "+1", 1.0);
   ast_statsd_log_string_va("PJSIP.registrations.state.%s", AST_STATSD_GAUGE, "+1", 1.0,
      sip_outbound_registration_status_str(state->client_state->status));

   if (!state->client_state->transport_name
      || !state->client_state->registration_name) {
      ao2_cleanup(state);
      return NULL;
   }

   /* Create name with seq number appended. */
   ast_taskprocessor_build_name(tps_name, sizeof(tps_name), "pjsip/outreg/%s",
      ast_sorcery_object_get_id(registration));

   state->client_state->serializer = ast_sip_create_serializer_group(tps_name,
      shutdown_group);
   if (!state->client_state->serializer) {
      ao2_cleanup(state);
      return NULL;
   }

   state->registration = ao2_bump(registration);
   return state;
}

/*! \brief Destructor function for registration information */
static void sip_outbound_registration_destroy(void *obj)
{
   struct sip_outbound_registration *registration = obj;

   ast_sip_auth_vector_destroy(&registration->outbound_auths);

   ast_string_field_free_memory(registration);
}

/*! \brief Allocator function for registration information */
static void *sip_outbound_registration_alloc(const char *name)
{
   struct sip_outbound_registration *registration;

   registration = ast_sorcery_generic_alloc(sizeof(*registration),
      sip_outbound_registration_destroy);
   if (!registration || ast_string_field_init(registration, 256)) {
      ao2_cleanup(registration);
      return NULL;
   }

   return registration;
}

/*! \brief Helper function which populates a pj_str_t with a contact header */
static int sip_dialog_create_contact(pj_pool_t *pool, pj_str_t *contact, const char *user,
   const pj_str_t *target, pjsip_tpselector *selector, const char *line, const char *header_params)
{
   pj_str_t tmp, local_addr;
   pjsip_uri *uri;
   pjsip_sip_uri *sip_uri;
   pjsip_transport_type_e type;
   int local_port;

   pj_strdup_with_null(pool, &tmp, target);

   if (!(uri = pjsip_parse_uri(pool, tmp.ptr, tmp.slen, 0)) ||
       (!PJSIP_URI_SCHEME_IS_SIP(uri) && !PJSIP_URI_SCHEME_IS_SIPS(uri))) {
      return -1;
   }

   sip_uri = pjsip_uri_get_uri(uri);

   type = pjsip_transport_get_type_from_name(&sip_uri->transport_param);
   if (PJSIP_URI_SCHEME_IS_SIPS(sip_uri)) {
      if (type == PJSIP_TRANSPORT_UNSPECIFIED
         || !(pjsip_transport_get_flag_from_type(type) & PJSIP_TRANSPORT_SECURE)) {
         type = PJSIP_TRANSPORT_TLS;
      }
   } else if (!sip_uri->transport_param.slen) {
      type = PJSIP_TRANSPORT_UDP;
   } else if (type == PJSIP_TRANSPORT_UNSPECIFIED) {
      return -1;
   }

   if (pj_strchr(&sip_uri->host, ':')) {
      type |= PJSIP_TRANSPORT_IPV6;
   }

   if (pjsip_tpmgr_find_local_addr(pjsip_endpt_get_tpmgr(ast_sip_get_pjsip_endpoint()),
      pool, type, selector, &local_addr, &local_port) != PJ_SUCCESS) {
      return -1;
   }

   if (!pj_strchr(&sip_uri->host, ':') && pj_strchr(&local_addr, ':')) {
      type |= PJSIP_TRANSPORT_IPV6;
   }

   contact->ptr = pj_pool_alloc(pool, PJSIP_MAX_URL_SIZE);
   contact->slen = pj_ansi_snprintf(contact->ptr, PJSIP_MAX_URL_SIZE,
      "<%s:%s@%s%.*s%s:%d%s%s%s%s>%s%s",
      ((pjsip_transport_get_flag_from_type(type) & PJSIP_TRANSPORT_SECURE) && PJSIP_URI_SCHEME_IS_SIPS(uri)) ? "sips" : "sip",
      user,
      (type & PJSIP_TRANSPORT_IPV6) ? "[" : "",
      (int)local_addr.slen,
      local_addr.ptr,
      (type & PJSIP_TRANSPORT_IPV6) ? "]" : "",
      local_port,
      (type != PJSIP_TRANSPORT_UDP && type != PJSIP_TRANSPORT_UDP6) ? ";transport=" : "",
      (type != PJSIP_TRANSPORT_UDP && type != PJSIP_TRANSPORT_UDP6) ? pjsip_transport_get_type_name(type) : "",
      !ast_strlen_zero(line) ? ";line=" : "",
      S_OR(line, ""),
      !ast_strlen_zero(header_params) ? ";" : "",
      S_OR(header_params, ""));

   return 0;
}

/*!
 * \internal
 * \brief Check if a registration can be reused
 *
 * This checks if the existing outbound registration's configuration differs from a newly-applied
 * outbound registration to see if the applied one.
 *
 * \param existing The pre-existing outbound registration
 * \param applied The newly-created registration
 */
static int can_reuse_registration(struct sip_outbound_registration *existing,
   struct sip_outbound_registration *applied)
{
   int rc = 1;
   struct ast_sorcery *sorcery = ast_sip_get_sorcery();
   struct ast_variable *ve = ast_sorcery_objectset_create(sorcery, existing);
   struct ast_variable *va = ast_sorcery_objectset_create(sorcery, applied);
   struct ast_variable *vc = NULL;

   if (ast_sorcery_changeset_create(ve, va, &vc) || vc != NULL) {
      rc = 0;
      ast_debug(4, "Registration '%s' changed.  Can't re-use.\n", ast_sorcery_object_get_id(existing));
   } else {
      ast_debug(4, "Registration '%s' didn't change.  Can re-use\n", ast_sorcery_object_get_id(existing));
   }

   ast_variables_destroy(ve);
   ast_variables_destroy(va);
   ast_variables_destroy(vc);

   return rc;
}

/* \brief Get google oauth2 access token using refresh token */
static const char *fetch_google_access_token(const struct ast_sip_auth *auth)
{
   char *cmd = NULL;
   const char *token;
   const char *url = "https://www.googleapis.com/oauth2/v3/token";
   char buf[4096];
   int res;
   struct ast_json_error error;
   struct ast_json *json;

   /* set timeout to be shorter than default 180s (also checks func_curl is available) */
   if (ast_func_write(NULL, "CURLOPT(conntimeout)", "10")) {
      ast_log(LOG_ERROR, "CURL is unavailable. This is required for Google OAuth 2.0 authentication. Please ensure it is loaded.\n");
      return NULL;
   }

   res = ast_asprintf(&cmd,
      "CURL(%s,client_id=%s&client_secret=%s&refresh_token=%s&grant_type=refresh_token)",
      url, auth->oauth_clientid, auth->oauth_secret, auth->refresh_token);
   if (res < 0) {
      return NULL;
   }

   ast_debug(2, "Performing Google OAuth 2.0 authentication using command: %s\n", cmd);

   buf[0] = '\0';
   res = ast_func_read(NULL, cmd, buf, sizeof(buf));
   ast_free(cmd);
   if (res) {
      ast_log(LOG_ERROR, "Could not retrieve Google OAuth 2.0 authentication\n");
      return NULL;
   }

   ast_debug(2, "Google OAuth 2.0 authentication returned: %s\n", buf);

   json = ast_json_load_string(buf, &error);
   if (!json) {
      ast_log(LOG_ERROR, "Could not parse Google OAuth 2.0 authentication: %d(%d) %s: '%s'\n",
         error.line, error.column, error.text, buf);
      return NULL;
   }

   token = ast_json_string_get(ast_json_object_get(json, "access_token"));
   if (!token) {
      ast_log(LOG_ERROR, "Could not find Google OAuth 2.0 access_token in: '%s'\n",
         buf);
   }
   token = ast_strdup(token);
   ast_json_unref(json);
   return token;
}

/*!
 * \internal
 * \brief Set pjsip registration context with any authentication credentials that need to be
 * sent in the initial registration request
 *
 * \param regc The pjsip registration context
 * \param auth_vector The vector of configured authentication credentials
 */
static int set_outbound_initial_authentication_credentials(pjsip_regc *regc,
      const struct ast_sip_auth_vector *auth_vector)
{
   size_t auth_size = AST_VECTOR_SIZE(auth_vector);
   struct ast_sip_auth *auths[auth_size];
   const char *access_token;
   pjsip_cred_info auth_creds[1];
   pjsip_auth_clt_pref prefs;
   int res = 0;
   int idx;

   memset(auths, 0, sizeof(auths));
   if (ast_sip_retrieve_auths(auth_vector, auths)) {
      res = -1;
      goto cleanup;
   }

   for (idx = 0; idx < auth_size; ++idx) {
      switch (auths[idx]->type) {
      case AST_SIP_AUTH_TYPE_GOOGLE_OAUTH:
         pj_cstr(&auth_creds[0].username, auths[idx]->auth_user);
         pj_cstr(&auth_creds[0].scheme, "Bearer");
         pj_cstr(&auth_creds[0].realm, auths[idx]->realm);
         ast_debug(2, "Obtaining Google OAuth access token\n");
         access_token = fetch_google_access_token(auths[idx]);
         if (!access_token) {
            ast_log(LOG_WARNING, "Obtaining Google OAuth access token failed\n");
            access_token = auths[idx]->auth_pass;
            res = -1;
         }
         ast_debug(2, "Setting data to '%s'\n", access_token);

         pj_cstr(&auth_creds[0].data, access_token);
         auth_creds[0].data_type = PJSIP_CRED_DATA_PLAIN_PASSWD;

         pjsip_regc_set_credentials(regc, 1, auth_creds);

         /* for oauth, send auth without waiting for unauthorized response */
         prefs.initial_auth = PJ_TRUE;
         pj_cstr(&prefs.algorithm, "oauth");
         pjsip_regc_set_prefs(regc, &prefs);

         if (access_token != auths[idx]->auth_pass) {
            ast_free((char *) access_token);
         }
         break;
      default:
         /* other cases handled after receiving auth rejection */
         break;
      }
   }

cleanup:
   ast_sip_cleanup_auths(auths, auth_size);
   return res;
}

/*! \brief Helper function that allocates a pjsip registration client and configures it */
static int sip_outbound_registration_regc_alloc(void *data)
{
   struct sip_outbound_registration_state *state = data;
   RAII_VAR(struct sip_outbound_registration *, registration,
       ao2_bump(state->registration), ao2_cleanup);
   pj_pool_t *pool;
   pj_str_t tmp;
   pjsip_uri *uri;
   pj_str_t server_uri, client_uri, contact_uri;
   pjsip_tpselector selector = { .type = PJSIP_TPSELECTOR_NONE, };

   pool = pjsip_endpt_create_pool(ast_sip_get_pjsip_endpoint(), "URI Validation", 256, 256);
   if (!pool) {
      ast_log(LOG_ERROR, "Could not create pool for URI validation on outbound registration '%s'\n",
         ast_sorcery_object_get_id(registration));
      return -1;
   }

   pj_strdup2_with_null(pool, &tmp, registration->server_uri);
   uri = pjsip_parse_uri(pool, tmp.ptr, tmp.slen, 0);
   if (!uri) {
      ast_log(LOG_ERROR, "Invalid server URI '%s' specified on outbound registration '%s'\n",
         registration->server_uri, ast_sorcery_object_get_id(registration));
      pjsip_endpt_release_pool(ast_sip_get_pjsip_endpoint(), pool);
      return -1;
   }

   pj_strdup2_with_null(pool, &tmp, registration->client_uri);
   uri = pjsip_parse_uri(pool, tmp.ptr, tmp.slen, 0);
   if (!uri) {
      ast_log(LOG_ERROR, "Invalid client URI '%s' specified on outbound registration '%s'\n",
         registration->client_uri, ast_sorcery_object_get_id(registration));
      pjsip_endpt_release_pool(ast_sip_get_pjsip_endpoint(), pool);
      return -1;
   }

   if (!ast_strlen_zero(registration->outbound_proxy)) {
      pj_strdup2_with_null(pool, &tmp, registration->outbound_proxy);
      uri = pjsip_parse_uri(pool, tmp.ptr, tmp.slen, 0);
      if (!uri) {
         ast_log(LOG_ERROR, "Invalid outbound proxy URI '%s' specified on outbound registration '%s'\n",
            registration->outbound_proxy, ast_sorcery_object_get_id(registration));
         pjsip_endpt_release_pool(ast_sip_get_pjsip_endpoint(), pool);
         return -1;
      }
   }

   pjsip_endpt_release_pool(ast_sip_get_pjsip_endpoint(), pool);


   ast_assert(state->client_state->client == NULL);
   if (pjsip_regc_create(ast_sip_get_pjsip_endpoint(), state->client_state,
         sip_outbound_registration_response_cb,
         &state->client_state->client) != PJ_SUCCESS) {
      return -1;
   }

   ast_sip_set_tpselector_from_transport_name(registration->transport, &selector);
   pjsip_regc_set_transport(state->client_state->client, &selector);

   if (!ast_strlen_zero(registration->outbound_proxy)) {
      pjsip_route_hdr route_set, *route;
      static const pj_str_t ROUTE_HNAME = { "Route", 5 };
      pj_str_t tmp;

      pj_list_init(&route_set);

      pj_strdup2_with_null(pjsip_regc_get_pool(state->client_state->client), &tmp,
         registration->outbound_proxy);
      route = pjsip_parse_hdr(pjsip_regc_get_pool(state->client_state->client),
         &ROUTE_HNAME, tmp.ptr, tmp.slen, NULL);
      if (!route) {
         ast_sip_tpselector_unref(&selector);
         return -1;
      }
      pj_list_insert_nodes_before(&route_set, route);

      pjsip_regc_set_route_set(state->client_state->client, &route_set);
   }

   if (state->registration->line) {
      ast_generate_random_string(state->client_state->line, sizeof(state->client_state->line));
   }

   pj_cstr(&server_uri, registration->server_uri);

   if (sip_dialog_create_contact(pjsip_regc_get_pool(state->client_state->client),
      &contact_uri, S_OR(registration->contact_user, "s"), &server_uri, &selector,
      state->client_state->line, registration->contact_header_params)) {
      ast_sip_tpselector_unref(&selector);
      return -1;
   }

   ast_sip_tpselector_unref(&selector);

   pj_cstr(&client_uri, registration->client_uri);
   if (pjsip_regc_init(state->client_state->client, &server_uri, &client_uri,
      &client_uri, 1, &contact_uri, registration->expiration) != PJ_SUCCESS) {
      return -1;
   }

   return 0;
}

/*! \brief Helper function which performs a single registration */
static int sip_outbound_registration_perform(void *data)
{
   struct sip_outbound_registration_state *state = data;
   struct sip_outbound_registration *registration = ao2_bump(state->registration);
   size_t i;

   /* Just in case the client state is being reused for this registration, free the auth information */
   ast_sip_auth_vector_destroy(&state->client_state->outbound_auths);

   AST_VECTOR_INIT(&state->client_state->outbound_auths, AST_VECTOR_SIZE(&registration->outbound_auths));
   for (i = 0; i < AST_VECTOR_SIZE(&registration->outbound_auths); ++i) {
      char *name = ast_strdup(AST_VECTOR_GET(&registration->outbound_auths, i));

      if (name && AST_VECTOR_APPEND(&state->client_state->outbound_auths, name)) {
         ast_free(name);
      }
   }
   state->client_state->retry_interval = registration->retry_interval;
   state->client_state->forbidden_retry_interval = registration->forbidden_retry_interval;
   state->client_state->fatal_retry_interval = registration->fatal_retry_interval;
   state->client_state->max_retries = registration->max_retries;
   state->client_state->retries = 0;
   state->client_state->support_path = registration->support_path;
   state->client_state->support_outbound = registration->support_outbound;
   state->client_state->auth_rejection_permanent = registration->auth_rejection_permanent;

   pjsip_regc_update_expires(state->client_state->client, registration->expiration);

   schedule_registration(state->client_state, (ast_random() % 10) + 1);

   ao2_ref(registration, -1);
   ao2_ref(state, -1);
   return 0;
}

/*! \brief Apply function which finds or allocates a state structure */
static int sip_outbound_registration_apply(const struct ast_sorcery *sorcery, void *obj)
{
   RAII_VAR(struct ao2_container *, states, ao2_global_obj_ref(current_states), ao2_cleanup);
   RAII_VAR(struct sip_outbound_registration_state *, state, NULL, ao2_cleanup);
   RAII_VAR(struct sip_outbound_registration_state *, new_state, NULL, ao2_cleanup);
   struct sip_outbound_registration *applied = obj;

   if (!states) {
      /* Global container has gone.  Likely shutting down. */
      return -1;
   }
   state = ao2_find(states, ast_sorcery_object_get_id(applied), OBJ_SEARCH_KEY);

   ast_debug(4, "Applying configuration to outbound registration '%s'\n", ast_sorcery_object_get_id(applied));

   if (ast_strlen_zero(applied->server_uri)) {
      ast_log(LOG_ERROR, "No server URI specified on outbound registration '%s'\n",
         ast_sorcery_object_get_id(applied));
      return -1;
   } else if (ast_sip_validate_uri_length(applied->server_uri)) {
         ast_log(LOG_ERROR, "Server URI or hostname length exceeds pjproject limit or is not a sip(s) uri: '%s'\n",
            ast_sorcery_object_get_id(applied));
         return -1;
   } else if (ast_strlen_zero(applied->client_uri)) {
      ast_log(LOG_ERROR, "No client URI specified on outbound registration '%s'\n",
         ast_sorcery_object_get_id(applied));
      return -1;
   } else if (ast_sip_validate_uri_length(applied->client_uri)) {
         ast_log(LOG_ERROR, "Client URI or hostname length exceeds pjproject limit or is not a sip(s) uri: '%s'\n",
            ast_sorcery_object_get_id(applied));
         return -1;
   } else if (applied->line && ast_strlen_zero(applied->endpoint)) {
      ast_log(LOG_ERROR, "Line support has been enabled on outbound registration '%s' without providing an endpoint\n",
         ast_sorcery_object_get_id(applied));
      return -1;
   } else if (!ast_strlen_zero(applied->endpoint) && !applied->line) {
      ast_log(LOG_ERROR, "An endpoint has been specified on outbound registration '%s' without enabling line support\n",
         ast_sorcery_object_get_id(applied));
      return -1;
   }

   if (state && can_reuse_registration(state->registration, applied)) {
      ast_debug(4,
         "No change between old configuration and new configuration on outbound registration '%s'. Using previous state\n",
         ast_sorcery_object_get_id(applied));

      /*
       * This is OK to replace without relinking the state in the
       * current_states container since state->registration and
       * applied have the same key.
       */
      ao2_lock(states);
      ao2_replace(state->registration, applied);
      ao2_unlock(states);
      return 0;
   }

   if (!(new_state = sip_outbound_registration_state_alloc(applied))) {
      return -1;
   }

   if (ast_sip_push_task_wait_serializer(new_state->client_state->serializer,
      sip_outbound_registration_regc_alloc, new_state)) {
      return -1;
   }

   if (ast_sip_push_task(new_state->client_state->serializer,
               sip_outbound_registration_perform, ao2_bump(new_state))) {
      ast_log(LOG_ERROR, "Failed to perform outbound registration on '%s'\n",
         ast_sorcery_object_get_id(new_state->registration));
      ao2_ref(new_state, -1);
      return -1;
   }

   ao2_lock(states);
   if (state) {
      ao2_unlink(states, state);
   }
   ao2_link(states, new_state);
   ao2_unlock(states);

   return 0;
}

static int outbound_auth_handler(const struct aco_option *opt, struct ast_variable *var, void *obj)
{
   struct sip_outbound_registration *registration = obj;

   return ast_sip_auth_vector_init(&registration->outbound_auths, var->value);
}

static int outbound_auths_to_str(const void *obj, const intptr_t *args, char **buf)
{
   const struct sip_outbound_registration *registration = obj;

   return ast_sip_auths_to_str(&registration->outbound_auths, buf);
}

static int outbound_auths_to_var_list(const void *obj, struct ast_variable **fields)
{
   const struct sip_outbound_registration *registration = obj;
   int i;
   struct ast_variable *head = NULL;

   for (i = 0; i < AST_VECTOR_SIZE(&registration->outbound_auths) ; i++) {
      ast_variable_list_append(&head, ast_variable_new("outbound_auth",
         AST_VECTOR_GET(&registration->outbound_auths, i), ""));
   }

   if (head) {
      *fields = head;
   }

   return 0;
}

static int unregister_task(void *obj)
{
   struct sip_outbound_registration_state *state = obj;
   struct pjsip_regc *client = state->client_state->client;
   pjsip_tx_data *tdata;
   pjsip_regc_info info;

   pjsip_regc_get_info(client, &info);
   ast_debug(1, "Unregistering contacts with server '%s' from client '%s'\n",
      state->registration->server_uri, state->registration->client_uri);

   cancel_registration(state->client_state);

   if (pjsip_regc_unregister(client, &tdata) == PJ_SUCCESS
      && add_configured_supported_headers(state->client_state, tdata)) {
      registration_client_send(state->client_state, tdata);
   }

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

static int queue_unregister(struct sip_outbound_registration_state *state)
{
   ao2_ref(state, +1);
   if (ast_sip_push_task(state->client_state->serializer, unregister_task, state)) {
      ao2_ref(state, -1);
      return -1;
   }

   return 0;
}

static int queue_register(struct sip_outbound_registration_state *state)
{
   ao2_ref(state, +1);
   if (ast_sip_push_task(state->client_state->serializer, sip_outbound_registration_perform, state)) {
      ao2_ref(state, -1);
      return -1;
   }

   return 0;
}

static void unregister_all(void)
{
   struct ao2_container *states;

   states = ao2_global_obj_ref(current_states);
   if (!states) {
      return;
   }

   /* Clean out all the states and let sorcery handle recreating the registrations */
   ao2_callback(states, OBJ_UNLINK | OBJ_NODATA | OBJ_MULTIPLE, NULL, NULL);
   ao2_ref(states, -1);
}

static void reregister_all(void)
{
   unregister_all();
   ast_sorcery_load_object(ast_sip_get_sorcery(), "registration");
}

static char *cli_complete_registration(const char *line, const char *word,
                   int pos, int state)
{
   char *result = NULL;
   int wordlen;
   int which = 0;
   struct sip_outbound_registration *registration;
   struct ao2_container *registrations;
   struct ao2_iterator i;

   if (pos != 3) {
      return NULL;
   }

   wordlen = strlen(word);
   if (wordlen == 0 && ++which > state) {
      return ast_strdup("*all");
   }

   registrations = ast_sorcery_retrieve_by_fields(ast_sip_get_sorcery(), "registration",
      AST_RETRIEVE_FLAG_MULTIPLE | AST_RETRIEVE_FLAG_ALL, NULL);
   if (!registrations) {
      return NULL;
   }

   i = ao2_iterator_init(registrations, 0);
   while ((registration = ao2_iterator_next(&i))) {
      const char *name = ast_sorcery_object_get_id(registration);

      if (!strncasecmp(word, name, wordlen) && ++which > state) {
         result = ast_strdup(name);
      }

      ao2_ref(registration, -1);
      if (result) {
         break;
      }
   }
   ao2_iterator_destroy(&i);

   ao2_ref(registrations, -1);
   return result;
}

static char *cli_unregister(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
   struct sip_outbound_registration_state *state;
   const char *registration_name;

   switch (cmd) {
   case CLI_INIT:
      e->command = "pjsip send unregister";
      e->usage =
         "Usage: pjsip send unregister <registration> | *all\n"
         "       Unregisters the specified (or all) outbound registration(s) "
         "and stops future registration attempts.\n";
      return NULL;
   case CLI_GENERATE:
      return cli_complete_registration(a->line, a->word, a->pos, a->n);
   }

   if (a->argc != 4) {
      return CLI_SHOWUSAGE;
   }

   registration_name = a->argv[3];

   if (strcmp(registration_name, "*all") == 0) {
      unregister_all();
      ast_cli(a->fd, "Unregister all queued\n");
      return CLI_SUCCESS;
   }

   state = get_state(registration_name);
   if (!state) {
      ast_cli(a->fd, "Unable to retrieve registration %s\n", registration_name);
      return CLI_FAILURE;
   }

   if (queue_unregister(state)) {
      ast_cli(a->fd, "Failed to queue unregistration\n");
   }

   ao2_ref(state, -1);
   return CLI_SUCCESS;
}

static char *cli_register(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
   struct sip_outbound_registration_state *state;
   const char *registration_name;

   switch (cmd) {
   case CLI_INIT:
      e->command = "pjsip send register";
      e->usage =
         "Usage: pjsip send register <registration> | *all \n"
         "       Unregisters the specified (or all) outbound "
         "registration(s) then starts registration(s) and schedules re-registrations.\n";
      return NULL;
   case CLI_GENERATE:
      return cli_complete_registration(a->line, a->word, a->pos, a->n);
   }

   if (a->argc != 4) {
      return CLI_SHOWUSAGE;
   }

   registration_name = a->argv[3];

   if (strcmp(registration_name, "*all") == 0) {
      reregister_all();
      ast_cli(a->fd, "Re-register all queued\n");
      return CLI_SUCCESS;
   }

   state = get_state(registration_name);
   if (!state) {
      ast_cli(a->fd, "Unable to retrieve registration %s\n", registration_name);
      return CLI_FAILURE;
   }

   /* We need to serialize the unregister and register so they need
    * to be queued as separate tasks.
    */
   if (queue_unregister(state)) {
      ast_cli(a->fd, "Failed to queue unregistration\n");
   } else if (queue_register(state)) {
      ast_cli(a->fd, "Failed to queue registration\n");
   }

   ao2_ref(state, -1);
   return CLI_SUCCESS;
}

static int ami_unregister(struct mansession *s, const struct message *m)
{
   const char *registration_name = astman_get_header(m, "Registration");
   struct sip_outbound_registration_state *state;

   if (ast_strlen_zero(registration_name)) {
      astman_send_error(s, m, "Registration parameter missing.");
      return 0;
   }

   if (strcmp(registration_name, "*all") == 0) {
      unregister_all();
      astman_send_ack(s, m, "Unregistrations queued.");
      return 0;
   }

   state = get_state(registration_name);
   if (!state) {
      astman_send_error(s, m, "Unable to retrieve registration entry\n");
      return 0;
   }

   if (queue_unregister(state)) {
      astman_send_ack(s, m, "Failed to queue unregistration");
   } else {
      astman_send_ack(s, m, "Unregistration sent");
   }

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

static int ami_register(struct mansession *s, const struct message *m)
{
   const char *registration_name = astman_get_header(m, "Registration");
   struct sip_outbound_registration_state *state;

   if (ast_strlen_zero(registration_name)) {
      astman_send_error(s, m, "Registration parameter missing.");
      return 0;
   }

   if (strcmp(registration_name, "*all") == 0) {
      reregister_all();
      astman_send_ack(s, m, "Reregistrations queued.");
      return 0;
   }

   state = get_state(registration_name);
   if (!state) {
      astman_send_error(s, m, "Unable to retrieve registration entry\n");
      return 0;
   }

   /* We need to serialize the unregister and register so they need
    * to be queued as separate tasks.
    */
   if (queue_unregister(state)) {
      astman_send_ack(s, m, "Failed to queue unregistration");
   } else if (queue_register(state)) {
      astman_send_ack(s, m, "Failed to queue unregistration");
   } else {
      astman_send_ack(s, m, "Reregistration sent");
   }

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

struct sip_ami_outbound {
   struct ast_sip_ami *ami;
   int registered;
   int not_registered;
   struct sip_outbound_registration *registration;
};

static int ami_outbound_registration_task(void *obj)
{
   struct sip_ami_outbound *ami = obj;
   struct ast_str *buf;
   struct sip_outbound_registration_state *state;

   buf = ast_sip_create_ami_event("OutboundRegistrationDetail", ami->ami);
   if (!buf) {
      return -1;
   }

   ast_sip_sorcery_object_to_ami(ami->registration, &buf);

   if ((state = get_state(ast_sorcery_object_get_id(ami->registration)))) {
      pjsip_regc_info info;

      if (state->client_state->status == SIP_REGISTRATION_REGISTERED) {
         ++ami->registered;
      } else {
         ++ami->not_registered;
      }

      ast_str_append(&buf, 0, "Status: %s\r\n",
         sip_outbound_registration_status_str(state->client_state->status));

      pjsip_regc_get_info(state->client_state->client, &info);
      ast_str_append(&buf, 0, "NextReg: %d\r\n", info.next_reg);
      ao2_ref(state, -1);
   }

   astman_append(ami->ami->s, "%s\r\n", ast_str_buffer(buf));
   ast_free(buf);

   return ast_sip_format_auths_ami(&ami->registration->outbound_auths, ami->ami);
}

static int ami_outbound_registration_detail(void *obj, void *arg, int flags)
{
   struct sip_ami_outbound *ami = arg;

   ami->registration = obj;
   return ast_sip_push_task_wait_servant(NULL, ami_outbound_registration_task, ami);
}

static int ami_show_outbound_registrations(struct mansession *s,
                  const struct message *m)
{
   struct ast_sip_ami ami = { .s = s, .m = m, .action_id = astman_get_header(m, "ActionID"), };
   struct sip_ami_outbound ami_outbound = { .ami = &ami };
   struct ao2_container *regs;

   regs = get_registrations();
   if (!regs) {
      astman_send_error(s, m, "Unable to retrieve "
              "outbound registrations\n");
      return -1;
   }

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

   ao2_callback(regs, OBJ_NODATA, ami_outbound_registration_detail, &ami_outbound);

   astman_send_list_complete_start(s, m, "OutboundRegistrationDetailComplete",
      ami_outbound.registered + ami_outbound.not_registered);
   astman_append(s,
      "Registered: %d\r\n"
      "NotRegistered: %d\r\n",
      ami_outbound.registered,
      ami_outbound.not_registered);
   astman_send_list_complete_end(s);

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

static struct ao2_container *cli_get_container(const char *regex)
{
   RAII_VAR(struct ao2_container *, container, NULL, ao2_cleanup);
   struct ao2_container *s_container;

   container = ast_sorcery_retrieve_by_regex(ast_sip_get_sorcery(), "registration", regex);
   if (!container) {
      return NULL;
   }

   s_container = ao2_container_alloc_list(AO2_ALLOC_OPT_LOCK_NOLOCK, 0,
      ast_sorcery_object_id_sort, ast_sorcery_object_id_compare);
   if (!s_container) {
      return NULL;
   }

   if (ao2_container_dup(s_container, container, 0)) {
      ao2_ref(s_container, -1);
      return NULL;
   }

   return s_container;
}

static int cli_iterator(void *container, ao2_callback_fn callback, void *args)
{
   ao2_callback(container, OBJ_NODATA, callback, args);

   return 0;
}

static void *cli_retrieve_by_id(const char *id)
{
   struct ao2_container *states;
   void *obj = ast_sorcery_retrieve_by_id(ast_sip_get_sorcery(), "registration", id);

   if (!obj) {
      /* if the object no longer exists then remove its state  */
      states = ao2_global_obj_ref(current_states);
      if (states) {
         ao2_find(states, id, OBJ_SEARCH_KEY | OBJ_UNLINK | OBJ_NODATA);
         ao2_ref(states, -1);
      }
   }

   return obj;
}

static int cli_print_header(void *obj, void *arg, int flags)
{
   struct ast_sip_cli_context *context = arg;

   ast_assert(context->output_buffer != NULL);

   ast_str_append(&context->output_buffer, 0,
      " <Registration/ServerURI..............................>  <Auth..........>  <Status.......>\n");

   return 0;
}

static int cli_print_body(void *obj, void *arg, int flags)
{
   struct sip_outbound_registration *registration = obj;
   struct ast_sip_cli_context *context = arg;
   const char *id = ast_sorcery_object_get_id(registration);
   struct sip_outbound_registration_state *state = get_state(id);
#define REGISTRATION_URI_FIELD_LEN  53

   ast_assert(context->output_buffer != NULL);

   ast_str_append(&context->output_buffer, 0, " %-s/%-*.*s  %-16s  %-16s\n",
      id,
      (int) (REGISTRATION_URI_FIELD_LEN - strlen(id)),
      (int) (REGISTRATION_URI_FIELD_LEN - strlen(id)),
      registration->server_uri,
      AST_VECTOR_SIZE(&registration->outbound_auths)
         ? AST_VECTOR_GET(&registration->outbound_auths, 0)
         : "n/a",
      (state ? sip_outbound_registration_status_str(state->client_state->status) : "Unregistered"));
   ao2_cleanup(state);

   if (context->show_details
      || (context->show_details_only_level_0 && context->indent_level == 0)) {
      ast_str_append(&context->output_buffer, 0, "\n");
      ast_sip_cli_print_sorcery_objectset(registration, context, 0);
   }

   return 0;
}

/*
 * A function pointer to callback needs to be within the
 * module in order to avoid problems with an undefined
 * symbol when the module is loaded.
 */
static char *my_cli_traverse_objects(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
   return ast_sip_cli_traverse_objects(e, cmd, a);
}

static struct ast_cli_entry cli_outbound_registration[] = {
   AST_CLI_DEFINE(cli_unregister, "Unregisters outbound registration target"),
   AST_CLI_DEFINE(cli_register, "Registers an outbound registration target"),
   AST_CLI_DEFINE(my_cli_traverse_objects, "List PJSIP Registrations",
      .command = "pjsip list registrations",
      .usage = "Usage: pjsip list registrations [ like <pattern> ]\n"
            "       List the configured PJSIP Registrations\n"
            "       Optional regular expression pattern is used to filter the list.\n"),
   AST_CLI_DEFINE(my_cli_traverse_objects, "Show PJSIP Registrations",
      .command = "pjsip show registrations",
      .usage = "Usage: pjsip show registrations [ like <pattern> ]\n"
            "       Show the configured PJSIP Registrations\n"
            "       Optional regular expression pattern is used to filter the list.\n"),
   AST_CLI_DEFINE(my_cli_traverse_objects, "Show PJSIP Registration",
      .command = "pjsip show registration",
      .usage = "Usage: pjsip show registration <id>\n"
             "       Show the configured PJSIP Registration\n"),
};

static struct ast_sip_cli_formatter_entry *cli_formatter;

static void auth_observer(const char *type)
{
   struct sip_outbound_registration *registration;
   struct sip_outbound_registration_state *state;
   struct ao2_container *regs;
   const char *registration_id;
   struct ao2_iterator i;

   ast_debug(4, "Auths updated. Checking for any outbound registrations that are in permanent rejected state so they can be retried\n");

   regs = ast_sorcery_retrieve_by_fields(ast_sip_get_sorcery(), "registration",
      AST_RETRIEVE_FLAG_MULTIPLE | AST_RETRIEVE_FLAG_ALL, NULL);
   if (!regs || ao2_container_count(regs) == 0) {
      ao2_cleanup(regs);
      return;
   }

   i = ao2_iterator_init(regs, 0);
   for (; (registration = ao2_iterator_next(&i)); ao2_ref(registration, -1)) {
      registration_id = ast_sorcery_object_get_id(registration);
      state = get_state(registration_id);
      if (state && state->client_state->status == SIP_REGISTRATION_REJECTED_PERMANENT) {
         ast_debug(4, "Trying outbound registration '%s' again\n", registration_id);

         if (ast_sip_push_task(state->client_state->serializer,
                     sip_outbound_registration_perform, ao2_bump(state))) {
            ast_log(LOG_ERROR, "Failed to perform outbound registration on '%s'\n", registration_id);
            ao2_ref(state, -1);
         }
      }
      ao2_cleanup(state);
   }
   ao2_iterator_destroy(&i);
   ao2_cleanup(regs);
}

static const struct ast_sorcery_observer observer_callbacks_auth = {
   .loaded = auth_observer,
};

static int check_state(void *obj, void *arg, int flags)
{
   struct sip_outbound_registration_state *state = obj;
   struct sip_outbound_registration *registration;

   registration = ast_sorcery_retrieve_by_id(ast_sip_get_sorcery(), "registration",
      ast_sorcery_object_get_id(state->registration));
   if (!registration) {
      /* This is a dead registration */
      return CMP_MATCH;
   }

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

/*!
 * \internal
 * \brief Observer to purge dead registration states.
 *
 * \param name Module name owning the sorcery instance.
 * \param sorcery Instance being observed.
 * \param object_type Name of object being observed.
 * \param reloaded Non-zero if the object is being reloaded.
 *
 * \return Nothing
 */
static void registration_loaded_observer(const char *name, const struct ast_sorcery *sorcery, const char *object_type, int reloaded)
{
   struct ao2_container *states;

   if (strcmp(object_type, "registration")) {
      /* Not interested */
      return;
   }

   states = ao2_global_obj_ref(current_states);
   if (!states) {
      /* Global container has gone.  Likely shutting down. */
      return;
   }

   /*
    * Refresh the current configured registrations. We don't need to hold
    * onto the objects, as the apply handler will cause their states to
    * be created appropriately.
    */
   ao2_cleanup(get_registrations());

   /* Now to purge dead registrations. */
   ao2_callback(states, OBJ_UNLINK | OBJ_NODATA | OBJ_MULTIPLE, check_state, NULL);
   ao2_ref(states, -1);
}

static const struct ast_sorcery_instance_observer observer_callbacks_registrations = {
   .object_type_loaded = registration_loaded_observer,
};

static void registration_deleted_observer(const void *obj)
{
   const struct sip_outbound_registration *registration = obj;
   struct ao2_container *states;

   states = ao2_global_obj_ref(current_states);
   if (!states) {
      /* Global container has gone.  Likely shutting down. */
      return;
   }

   ao2_find(states, ast_sorcery_object_get_id(registration), OBJ_UNLINK | OBJ_NODATA | OBJ_SEARCH_KEY);

   ao2_ref(states, -1);
}

static const struct ast_sorcery_observer registration_observer = {
   .deleted = registration_deleted_observer,
};

static void network_change_stasis_cb(void *data, struct stasis_subscription *sub, struct stasis_message *message)
{
   /* This callback is only concerned with network change messages from the system topic. */
   if (stasis_message_type(message) != ast_network_change_type()) {
      return;
   }
   ast_debug(3, "Received network change event\n");

   reregister_all();
}

static int unload_module(void)
{
   int remaining;

   network_change_sub = stasis_unsubscribe_and_join(network_change_sub);

   ast_manager_unregister("PJSIPShowRegistrationsOutbound");
   ast_manager_unregister("PJSIPUnregister");
   ast_manager_unregister("PJSIPRegister");

   ast_cli_unregister_multiple(cli_outbound_registration, ARRAY_LEN(cli_outbound_registration));
   ast_sip_unregister_cli_formatter(cli_formatter);
   cli_formatter = NULL;

   ast_sip_unregister_endpoint_identifier(&line_identifier);

   ast_sorcery_observer_remove(ast_sip_get_sorcery(), "auth", &observer_callbacks_auth);
   ast_sorcery_instance_observer_remove(ast_sip_get_sorcery(), &observer_callbacks_registrations);

   ast_sorcery_object_unregister(ast_sip_get_sorcery(), "registration");

   ao2_global_obj_release(current_states);

   ast_sip_transport_monitor_unregister_all(registration_transport_shutdown_cb, NULL, NULL);

   /* Wait for registration serializers to get destroyed. */
   ast_debug(2, "Waiting for registration transactions to complete for unload.\n");
   remaining = ast_serializer_shutdown_group_join(shutdown_group, MAX_UNLOAD_TIMEOUT_TIME);
   if (remaining) {
      /*
       * NOTE: We probably have a sip_outbound_registration_client_state
       * ref leak if the remaining count cannot reach zero after a few
       * minutes of trying to unload.
       */
      ast_log(LOG_WARNING, "Unload incomplete.  Could not stop %d outbound registrations.  Try again later.\n",
         remaining);
      return -1;
   }

   ast_debug(2, "Successful shutdown.\n");

   ao2_cleanup(shutdown_group);
   shutdown_group = NULL;

   return 0;
}

static int load_module(void)
{
   struct ao2_container *new_states;

   shutdown_group = ast_serializer_shutdown_group_alloc();
   if (!shutdown_group) {
      return AST_MODULE_LOAD_DECLINE;
   }

   /* Create outbound registration states container. */
   new_states = ao2_container_alloc_hash(AO2_ALLOC_OPT_LOCK_MUTEX, 0,
      DEFAULT_STATE_BUCKETS, registration_state_hash, NULL, registration_state_cmp);
   if (!new_states) {
      ast_log(LOG_ERROR, "Unable to allocate registration states container\n");
      unload_module();
      return AST_MODULE_LOAD_DECLINE;
   }
   ao2_global_obj_replace_unref(current_states, new_states);
   ao2_ref(new_states, -1);

   /*
    * Register sorcery object descriptions.
    */
   ast_sorcery_apply_config(ast_sip_get_sorcery(), "res_pjsip_outbound_registration");
   ast_sorcery_apply_default(ast_sip_get_sorcery(), "registration", "config", "pjsip.conf,criteria=type=registration");

   if (ast_sorcery_object_register(ast_sip_get_sorcery(), "registration", sip_outbound_registration_alloc, NULL, sip_outbound_registration_apply)) {
      unload_module();
      return AST_MODULE_LOAD_DECLINE;
   }

   ast_sorcery_object_field_register(ast_sip_get_sorcery(), "registration", "type", "", OPT_NOOP_T, 0, 0);
   ast_sorcery_object_field_register(ast_sip_get_sorcery(), "registration", "server_uri", "", OPT_STRINGFIELD_T, 0, STRFLDSET(struct sip_outbound_registration, server_uri));
   ast_sorcery_object_field_register(ast_sip_get_sorcery(), "registration", "client_uri", "", OPT_STRINGFIELD_T, 0, STRFLDSET(struct sip_outbound_registration, client_uri));
   ast_sorcery_object_field_register(ast_sip_get_sorcery(), "registration", "contact_user", "", OPT_STRINGFIELD_T, 0, STRFLDSET(struct sip_outbound_registration, contact_user));
   ast_sorcery_object_field_register(ast_sip_get_sorcery(), "registration", "contact_header_params", "", OPT_STRINGFIELD_T, 0, STRFLDSET(struct sip_outbound_registration, contact_header_params));
   ast_sorcery_object_field_register(ast_sip_get_sorcery(), "registration", "transport", "", OPT_STRINGFIELD_T, 0, STRFLDSET(struct sip_outbound_registration, transport));
   ast_sorcery_object_field_register(ast_sip_get_sorcery(), "registration", "outbound_proxy", "", OPT_STRINGFIELD_T, 0, STRFLDSET(struct sip_outbound_registration, outbound_proxy));
   ast_sorcery_object_field_register(ast_sip_get_sorcery(), "registration", "expiration", "3600", OPT_UINT_T, 0, FLDSET(struct sip_outbound_registration, expiration));
   ast_sorcery_object_field_register(ast_sip_get_sorcery(), "registration", "retry_interval", "60", OPT_UINT_T, 0, FLDSET(struct sip_outbound_registration, retry_interval));
   ast_sorcery_object_field_register(ast_sip_get_sorcery(), "registration", "forbidden_retry_interval", "0", OPT_UINT_T, 0, FLDSET(struct sip_outbound_registration, forbidden_retry_interval));
   ast_sorcery_object_field_register(ast_sip_get_sorcery(), "registration", "fatal_retry_interval", "0", OPT_UINT_T, 0, FLDSET(struct sip_outbound_registration, fatal_retry_interval));
   ast_sorcery_object_field_register(ast_sip_get_sorcery(), "registration", "max_retries", "10", OPT_UINT_T, 0, FLDSET(struct sip_outbound_registration, max_retries));
   ast_sorcery_object_field_register(ast_sip_get_sorcery(), "registration", "auth_rejection_permanent", "yes", OPT_BOOL_T, 1, FLDSET(struct sip_outbound_registration, auth_rejection_permanent));
   ast_sorcery_object_field_register_custom(ast_sip_get_sorcery(), "registration", "outbound_auth", "", outbound_auth_handler, outbound_auths_to_str, outbound_auths_to_var_list, 0, 0);
   ast_sorcery_object_field_register(ast_sip_get_sorcery(), "registration", "support_path", "no", OPT_BOOL_T, 1, FLDSET(struct sip_outbound_registration, support_path));
   ast_sorcery_object_field_register(ast_sip_get_sorcery(), "registration", "support_outbound", "no", OPT_YESNO_T, 1, FLDSET(struct sip_outbound_registration, support_outbound));
   ast_sorcery_object_field_register(ast_sip_get_sorcery(), "registration", "line", "no", OPT_BOOL_T, 1, FLDSET(struct sip_outbound_registration, line));
   ast_sorcery_object_field_register(ast_sip_get_sorcery(), "registration", "endpoint", "", OPT_STRINGFIELD_T, 0, STRFLDSET(struct sip_outbound_registration, endpoint));

   /*
    * Register sorcery observers.
    */
   if (ast_sorcery_instance_observer_add(ast_sip_get_sorcery(),
      &observer_callbacks_registrations)
      || ast_sorcery_observer_add(ast_sip_get_sorcery(), "auth",
         &observer_callbacks_auth)
      || ast_sorcery_observer_add(ast_sip_get_sorcery(), "registration",
         &registration_observer)) {
      ast_log(LOG_ERROR, "Unable to register observers.\n");
      unload_module();
      return AST_MODULE_LOAD_DECLINE;
   }

   /* Register how this module identifies endpoints. */
   ast_sip_register_endpoint_identifier(&line_identifier);

   /* Register CLI commands. */
   cli_formatter = ao2_alloc(sizeof(struct ast_sip_cli_formatter_entry), NULL);
   if (!cli_formatter) {
      ast_log(LOG_ERROR, "Unable to allocate memory for cli formatter\n");
      unload_module();
      return AST_MODULE_LOAD_DECLINE;
   }
   cli_formatter->name = "registration";
   cli_formatter->print_header = cli_print_header;
   cli_formatter->print_body = cli_print_body;
   cli_formatter->get_container = cli_get_container;
   cli_formatter->iterate = cli_iterator;
   cli_formatter->get_id = ast_sorcery_object_get_id;
   cli_formatter->retrieve_by_id = cli_retrieve_by_id;
   ast_sip_register_cli_formatter(cli_formatter);
   ast_cli_register_multiple(cli_outbound_registration, ARRAY_LEN(cli_outbound_registration));

   /* Register AMI actions. */
   ast_manager_register_xml("PJSIPUnregister", EVENT_FLAG_SYSTEM | EVENT_FLAG_REPORTING, ami_unregister);
   ast_manager_register_xml("PJSIPRegister", EVENT_FLAG_SYSTEM | EVENT_FLAG_REPORTING, ami_register);
   ast_manager_register_xml("PJSIPShowRegistrationsOutbound", EVENT_FLAG_SYSTEM | EVENT_FLAG_REPORTING, ami_show_outbound_registrations);

   /* Clear any previous statsd gauges in case we weren't shutdown cleanly */
   ast_statsd_log("PJSIP.registrations.count", AST_STATSD_GAUGE, 0);
   ast_statsd_log("PJSIP.registrations.state.Registered", AST_STATSD_GAUGE, 0);
   ast_statsd_log("PJSIP.registrations.state.Unregistered", AST_STATSD_GAUGE, 0);
   ast_statsd_log("PJSIP.registrations.state.Rejected", AST_STATSD_GAUGE, 0);

   /* Load configuration objects */
   ast_sorcery_load_object(ast_sip_get_sorcery(), "registration");

   network_change_sub = stasis_subscribe(ast_system_topic(),
      network_change_stasis_cb, NULL);
   stasis_subscription_accept_message_type(network_change_sub, ast_network_change_type());
   stasis_subscription_set_filter(network_change_sub, STASIS_SUBSCRIPTION_FILTER_SELECTIVE);

   return AST_MODULE_LOAD_SUCCESS;
}

static int reload_module(void)
{
   ast_sorcery_reload_object(ast_sip_get_sorcery(), "registration");
   return 0;
}

AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "PJSIP Outbound Registration Support",
   .support_level = AST_MODULE_SUPPORT_CORE,
   .load = load_module,
   .reload = reload_module,
   .unload = unload_module,
   .load_pri = AST_MODPRI_APP_DEPEND,
   .requires = "res_pjsip",
   .optional_modules = "res_statsd",
);