The large GULP->PJSIP renaming effort.

The general gist is to have a clear boundary between old SIP stuff
and new SIP stuff by having the word "SIP" for old stuff and "PJSIP"
for new stuff. Here's a brief rundown of the changes:

* The word "Gulp" in dialstrings, functions, and CLI commands is now
  "PJSIP"
* chan_gulp.c is now chan_pjsip.c
* Function names in chan_gulp.c that were "gulp_*" are now "chan_pjsip_*"
* All files that were "res_sip*" are now "res_pjsip*"
* The "res_sip" directory is now "res_pjsip"
* Files in the "res_pjsip" directory that began with "sip_*" are now "pjsip_*"
* The configuration file is now "pjsip.conf" instead of "res_sip.conf"
* The module info for all PJSIP-related files now uses "PJSIP" instead of "SIP"
* CLI and AMI commands created by Asterisk's PJSIP modules now have "pjsip" as
the starting word instead of "sip"



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@395764 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 749 insertions, 0 deletions

diff --git a/res/res_pjsip_outbound_registration.c b/res/res_pjsip_outbound_registration.c
new file mode 100644
index 000000000..6d9368ec1
--- /dev/null
+++ b/res/res_pjsip_outbound_registration.c
@@ -0,0 +1,749 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2013, Digium, Inc.
+ *
+ * Joshua Colp <jcolp@digium.com>
+ *
+ * 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>
+	<support_level>core</support_level>
+ ***/
+
+#include "asterisk.h"
+
+#include <pjsip.h>
+#include <pjsip_ua.h>
+
+#include "asterisk/res_pjsip.h"
+#include "asterisk/module.h"
+#include "asterisk/taskprocessor.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>
+				</configOption>
+				<configOption name="contact_user">
+					<synopsis>Contact User to use in request</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>
+				</configOption>
+				<configOption name="outbound_auth" default="">
+					<synopsis>Authentication object to be used for outbound registrations.</synopsis>
+				</configOption>
+				<configOption name="outbound_proxy" default="">
+					<synopsis>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="server_uri">
+					<synopsis>SIP URI of the server to register against</synopsis>
+				</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="type">
+					<synopsis>Must be of type 'registration'.</synopsis>
+				</configOption>
+			</configObject>
+		</configFile>
+	</configInfo>
+ ***/
+
+/*! \brief Amount of buffer time (in seconds) before expiration that we re-register at */
+#define REREGISTER_BUFFER_TIME 10
+
+/*! \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 has been stopped */
+	SIP_REGISTRATION_STOPPED,
+};
+
+/*! \brief Outbound registration client state information (persists for lifetime of regc) */
+struct sip_outbound_registration_client_state {
+	/*! \brief Current status of this registration */
+	enum sip_outbound_registration_status status;
+	/*! \brief Outbound registration client */
+	pjsip_regc *client;
+	/*! \brief Timer entry for retrying on temporal responses */
+	pj_timer_entry timer;
+	/*! \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 Treat authentication challenges that we cannot handle as permanent failures */
+	unsigned int auth_rejection_permanent;
+	/*! \brief Serializer for stuff and things */
+	struct ast_taskprocessor *serializer;
+	/*! \brief Configured authentication credentials */
+	struct ast_sip_auth_array outbound_auths;
+	/*! \brief Number of configured auths */
+	size_t num_outbound_auths;
+	/*! \brief Registration should be destroyed after completion of transaction */
+	unsigned int destroy:1;
+};
+
+/*! \brief Outbound registration state information (persists for lifetime that registration should exist) */
+struct sip_outbound_registration_state {
+	/*! \brief Client state information */
+	struct sip_outbound_registration_client_state *client_state;
+};
+
+/*! \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);
+		/*! \brief Explicit transport to use for registration */
+		AST_STRING_FIELD(transport);
+		/*! \brief Outbound proxy to use */
+		AST_STRING_FIELD(outbound_proxy);
+	);
+	/*! \brief Requested expiration time */
+	unsigned int expiration;
+	/*! \brief Interval at which retries should occur for temporal responses */
+	unsigned int 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 Outbound registration state */
+	struct sip_outbound_registration_state *state;
+	/*! \brief Configured authentication credentials */
+	struct ast_sip_auth_array outbound_auths;
+	/*! \brief Number of configured auths */
+	size_t num_outbound_auths;
+};
+
+/*! \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(pjsip_endpt_get_timer_heap(ast_sip_get_pjsip_endpoint()), &client_state->timer)) {
+		/* The timer was successfully cancelled, drop the refcount of client_state */
+		ao2_ref(client_state, -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;
+
+	cancel_registration(client_state);
+
+	if ((client_state->status == SIP_REGISTRATION_STOPPED) ||
+		(pjsip_regc_register(client_state->client, PJ_FALSE, &tdata) != PJ_SUCCESS)) {
+		return 0;
+	}
+
+	/* Due to the registration the callback may now get called, so bump the ref count */
+	ao2_ref(client_state, +1);
+	if (pjsip_regc_send(client_state->client, tdata) != PJ_SUCCESS) {
+		ao2_ref(client_state, -1);
+		pjsip_tx_data_dec_ref(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)
+{
+	RAII_VAR(struct sip_outbound_registration_client_state *, client_state, entry->user_data, ao2_cleanup);
+
+	ao2_ref(client_state, +1);
+	if (ast_sip_push_task(client_state->serializer, handle_client_registration, client_state)) {
+		ast_log(LOG_WARNING, "Failed to pass outbound registration to threadpool\n");
+		ao2_ref(client_state, -1);
+	}
+
+	entry->id = 0;
+}
+
+/*! \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, };
+
+	cancel_registration(client_state);
+
+	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 pass timed registration to scheduler\n");
+		ao2_ref(client_state, -1);
+	}
+}
+
+/*! \brief Callback function for unregistering (potentially) and destroying state */
+static int handle_client_state_destruction(void *data)
+{
+	RAII_VAR(struct sip_outbound_registration_client_state *, client_state, data, ao2_cleanup);
+	pjsip_regc_info info;
+
+	cancel_registration(client_state);
+
+	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 */
+		client_state->destroy = 1;
+		return 0;
+	}
+
+	if (client_state->status != SIP_REGISTRATION_UNREGISTERED && client_state->status != SIP_REGISTRATION_REJECTED_PERMANENT) {
+		pjsip_tx_data *tdata;
+
+		if (pjsip_regc_unregister(client_state->client, &tdata) == PJ_SUCCESS) {
+			pjsip_regc_send(client_state->client, tdata);
+		}
+	}
+
+	pjsip_regc_destroy(client_state->client);
+
+	client_state->status = SIP_REGISTRATION_STOPPED;
+	ast_sip_auth_array_destroy(&client_state->outbound_auths);
+
+	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 The response transaction */
+	pjsip_transaction *tsx;
+};
+
+/*! \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);
+	}
+
+	ao2_cleanup(response->client_state);
+}
+
+/* \brief Helper funtion 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;
+	}
+}
+
+/*! \brief Callback function for handling a response to a registration attempt */
+static int handle_registration_response(void *data)
+{
+	RAII_VAR(struct registration_response *, response, data, ao2_cleanup);
+	pjsip_regc_info info;
+	char server_uri[PJSIP_MAX_URL_SIZE], client_uri[PJSIP_MAX_URL_SIZE];
+
+	if (response->client_state->status == SIP_REGISTRATION_STOPPED) {
+		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));
+
+	if (response->code == 401 || response->code == 407) {
+		pjsip_tx_data *tdata;
+		if (!ast_sip_create_request_with_auth(&response->client_state->outbound_auths,
+				response->rdata, response->tsx, &tdata)) {
+			pjsip_regc_send(response->client_state->client, tdata);
+			return 0;
+		}
+		/* Otherwise, fall through so the failure is processed appropriately */
+	}
+
+	if (PJSIP_IS_STATUS_IN_CLASS(response->code, 200)) {
+		/* If the registration went fine simply reschedule registration for the future */
+		response->client_state->status = SIP_REGISTRATION_REGISTERED;
+		response->client_state->retries = 0;
+		schedule_registration(response->client_state, response->expiration - REREGISTER_BUFFER_TIME);
+	} else if (response->retry_after) {
+		/* If we have been instructed to retry after a period of time, schedule it as such */
+		response->client_state->status = SIP_REGISTRATION_REJECTED_TEMPORARY;
+		schedule_registration(response->client_state, response->retry_after);
+		ast_log(LOG_WARNING, "Temporal response '%d' received from '%s' on registration attempt to '%s', instructed to retry in '%d'\n",
+			response->code, server_uri, client_uri, response->retry_after);
+	} 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 */
+			response->client_state->status = 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->status = SIP_REGISTRATION_REJECTED_TEMPORARY;
+			response->client_state->retries++;
+			schedule_registration(response->client_state, response->client_state->retry_interval);
+			ast_log(LOG_WARNING, "Temporal response '%d' received from '%s' on registration attempt to '%s', retrying in '%d' seconds\n",
+				response->code, server_uri, client_uri, response->client_state->retry_interval);
+		}
+	} else {
+		/* Finally if there's no hope of registering give up */
+		response->client_state->status = SIP_REGISTRATION_REJECTED_PERMANENT;
+		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);
+	}
+
+	/* If deferred destruction is in use see if we need to destroy now */
+	if (response->client_state->destroy) {
+		handle_client_state_destruction(response->client_state);
+	}
+
+	return 0;
+}
+
+/*! \brief Callback function for outbound registration client */
+static void sip_outbound_registration_response_cb(struct pjsip_regc_cbparam *param)
+{
+	RAII_VAR(struct sip_outbound_registration_client_state *, client_state, param->token, ao2_cleanup);
+	struct registration_response *response = ao2_alloc(sizeof(*response), registration_response_destroy);
+
+	response->code = param->code;
+	response->expiration = param->expiration;
+	response->client_state = client_state;
+
+	if (param->rdata) {
+		struct pjsip_retry_after_hdr *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;
+		response->tsx = pjsip_rdata_get_tsx(param->rdata);
+		pjsip_rx_data_clone(param->rdata, 0, &response->rdata);
+	}
+
+	ao2_ref(response->client_state, +1);
+
+	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;
+
+	if (!state->client_state) {
+		return;
+	}
+
+	if (state->client_state->serializer && 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_taskprocessor_unreference(client_state->serializer);
+}
+
+/*! \brief Allocator function for registration state */
+static struct sip_outbound_registration_state *sip_outbound_registration_state_alloc(void)
+{
+	struct sip_outbound_registration_state *state = ao2_alloc(sizeof(*state), sip_outbound_registration_state_destroy);
+
+	if (!state || !(state->client_state = ao2_alloc(sizeof(*state->client_state), sip_outbound_registration_client_state_destroy))) {
+		ao2_cleanup(state);
+		return NULL;
+	}
+
+	if ((pjsip_regc_create(ast_sip_get_pjsip_endpoint(), state->client_state, sip_outbound_registration_response_cb, &state->client_state->client) != PJ_SUCCESS) ||
+		!(state->client_state->serializer = ast_sip_create_serializer())) {
+		/* This is on purpose, normal operation will have it be deallocated within the serializer */
+		pjsip_regc_destroy(state->client_state->client);
+		ao2_cleanup(state->client_state);
+		ao2_cleanup(state);
+		return NULL;
+	}
+
+	state->client_state->status = SIP_REGISTRATION_UNREGISTERED;
+	state->client_state->timer.user_data = state->client_state;
+	state->client_state->timer.cb = sip_outbound_registration_timer_cb;
+
+	return state;
+}
+
+/*! \brief Destructor function for registration information */
+static void sip_outbound_registration_destroy(void *obj)
+{
+	struct sip_outbound_registration *registration = obj;
+
+	ao2_cleanup(registration->state);
+	ast_sip_auth_array_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 = 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)
+{
+	pj_str_t tmp, local_addr;
+	pjsip_uri *uri;
+	pjsip_sip_uri *sip_uri;
+	pjsip_transport_type_e type = PJSIP_TRANSPORT_UNSPECIFIED;
+	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);
+
+	if (PJSIP_URI_SCHEME_IS_SIPS(sip_uri)) {
+		type = PJSIP_TRANSPORT_TLS;
+	} else if (!sip_uri->transport_param.slen) {
+		type = PJSIP_TRANSPORT_UDP;
+	} else {
+		type = pjsip_transport_get_type_from_name(&sip_uri->transport_param);
+	}
+
+	if (type == PJSIP_TRANSPORT_UNSPECIFIED) {
+		return -1;
+	}
+
+	if (pj_strchr(&sip_uri->host, ':')) {
+		type = (pjsip_transport_type_e)(((int)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_type_e)(((int)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>",
+				      (pjsip_transport_get_flag_from_type(type) & PJSIP_TRANSPORT_SECURE) ? "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) : "");
+
+	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 i;
+
+	if (strcmp(existing->server_uri, applied->server_uri) || strcmp(existing->client_uri, applied->client_uri) ||
+		strcmp(existing->transport, applied->transport) || strcmp(existing->contact_user, applied->contact_user) ||
+		strcmp(existing->outbound_proxy, applied->outbound_proxy) || existing->num_outbound_auths != applied->num_outbound_auths ||
+		existing->auth_rejection_permanent != applied->auth_rejection_permanent) {
+		return 0;
+	}
+
+	for (i = 0; i < existing->num_outbound_auths; ++i) {
+		if (strcmp(existing->outbound_auths.names[i], applied->outbound_auths.names[i])) {
+			return 0;
+		}
+	}
+
+	return 1;
+}
+
+/*! \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 *registration = data;
+	pj_str_t server_uri, client_uri, contact_uri;
+	pjsip_tpselector selector = { .type = PJSIP_TPSELECTOR_NONE, };
+
+	if (!ast_strlen_zero(registration->transport)) {
+		RAII_VAR(struct ast_sip_transport *, transport, ast_sorcery_retrieve_by_id(ast_sip_get_sorcery(), "transport", registration->transport), ao2_cleanup);
+
+		if (!transport || !transport->state) {
+			return -1;
+		}
+
+		if (transport->state->transport) {
+			selector.type = PJSIP_TPSELECTOR_TRANSPORT;
+			selector.u.transport = transport->state->transport;
+		} else if (transport->state->factory) {
+			selector.type = PJSIP_TPSELECTOR_LISTENER;
+			selector.u.listener = transport->state->factory;
+		} else {
+			return -1;
+		}
+	}
+
+	pjsip_regc_set_transport(registration->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(registration->state->client_state->client), &tmp, registration->outbound_proxy);
+		if (!(route = pjsip_parse_hdr(pjsip_regc_get_pool(registration->state->client_state->client), &ROUTE_HNAME, tmp.ptr, tmp.slen, NULL))) {
+			return -1;
+		}
+		pj_list_push_back(&route_set, route);
+
+		pjsip_regc_set_route_set(registration->state->client_state->client, &route_set);
+	}
+
+	pj_cstr(&server_uri, registration->server_uri);
+
+	if (sip_dialog_create_contact(pjsip_regc_get_pool(registration->state->client_state->client), &contact_uri, S_OR(registration->contact_user, "s"), &server_uri, &selector)) {
+		return -1;
+	}
+
+	pj_cstr(&client_uri, registration->client_uri);
+
+	if (pjsip_regc_init(registration->state->client_state->client, &server_uri, &client_uri, &client_uri, 1, &contact_uri, registration->expiration) != PJ_SUCCESS) {
+		return -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 sip_outbound_registration *, existing, ast_sorcery_retrieve_by_id(sorcery, "registration", ast_sorcery_object_get_id(obj)), ao2_cleanup);
+	struct sip_outbound_registration *applied = obj;
+
+	if (!existing) {
+		/* If no existing registration exists we can just start fresh easily */
+		applied->state = sip_outbound_registration_state_alloc();
+	} else {
+		/* If there is an existing registration things are more complicated, we can immediately reuse this state if most stuff remains unchanged */
+		if (can_reuse_registration(existing, applied)) {
+			applied->state = existing->state;
+			ao2_ref(applied->state, +1);
+			return 0;
+		}
+		applied->state = sip_outbound_registration_state_alloc();
+	}
+
+	if (!applied->state) {
+		return -1;
+	}
+
+	return ast_sip_push_task_synchronous(NULL, sip_outbound_registration_regc_alloc, applied);
+}
+
+/*! \brief Helper function which performs a single registration */
+static int sip_outbound_registration_perform(void *data)
+{
+	RAII_VAR(struct sip_outbound_registration *, registration, data, ao2_cleanup);
+	size_t i;
+
+	/* Just in case the client state is being reused for this registration, free the auth information */
+	ast_sip_auth_array_destroy(&registration->state->client_state->outbound_auths);
+
+	registration->state->client_state->outbound_auths.names = ast_calloc(registration->outbound_auths.num, sizeof(char *));
+	for (i = 0; i < registration->outbound_auths.num; ++i) {
+		registration->state->client_state->outbound_auths.names[i] = ast_strdup(registration->outbound_auths.names[i]);
+	}
+	registration->state->client_state->outbound_auths.num = registration->outbound_auths.num;
+	registration->state->client_state->retry_interval = registration->retry_interval;
+	registration->state->client_state->max_retries = registration->max_retries;
+	registration->state->client_state->retries = 0;
+
+	pjsip_regc_update_expires(registration->state->client_state->client, registration->expiration);
+
+	schedule_registration(registration->state->client_state, (ast_random() % 10) + 1);
+
+	return 0;
+}
+
+/*! \brief Helper function which performs all registrations */
+static void sip_outbound_registration_perform_all(void)
+{
+	RAII_VAR(struct ao2_container *, registrations, ast_sorcery_retrieve_by_fields(ast_sip_get_sorcery(), "registration", AST_RETRIEVE_FLAG_MULTIPLE | AST_RETRIEVE_FLAG_ALL, NULL), ao2_cleanup);
+	struct ao2_iterator i;
+	struct sip_outbound_registration *registration;
+
+	if (!registrations) {
+		return;
+	}
+
+	i = ao2_iterator_init(registrations, 0);
+	while ((registration = ao2_iterator_next(&i))) {
+		if (ast_sip_push_task(registration->state->client_state->serializer, sip_outbound_registration_perform, registration)) {
+			ast_log(LOG_ERROR, "Failed to perform outbound registration on '%s'\n", ast_sorcery_object_get_id(registration));
+			ao2_ref(registration, -1);
+		}
+	}
+	ao2_iterator_destroy(&i);
+}
+
+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_array_init(&registration->outbound_auths, var->value);
+}
+
+static int load_module(void)
+{
+	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)) {
+		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", "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", "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, NULL, 0, 0);
+	ast_sorcery_reload_object(ast_sip_get_sorcery(), "registration");
+	sip_outbound_registration_perform_all();
+
+	return AST_MODULE_LOAD_SUCCESS;
+}
+
+static int reload_module(void)
+{
+	ast_sorcery_reload_object(ast_sip_get_sorcery(), "registration");
+	sip_outbound_registration_perform_all();
+	return 0;
+}
+
+static int unload_module(void)
+{
+	return 0;
+}
+
+AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "PJSIP Outbound Registration Support",
+		.load = load_module,
+		.reload = reload_module,
+		.unload = unload_module,
+		.load_pri = AST_MODPRI_APP_DEPEND,
+	       );