PJSIP: Add Path header support

This adds Path support to chan_pjsip in res_pjsip_path.c with minimal
additions in res_pjsip_registrar.c to store the path and additions in
res_pjsip_outbound_registration.c to enable advertisement of path
support to registrars and intervening proxies.

Path information is stored on contacts and is enabled via Address of
Record (AoRs) and Registration configuration sections.

While adding path support, it became necessary to be able to add SIP
supplements that handled messages outside of sessions, so a framework
for handling these types of hooks was added in parallel to the
already-existing session supplements and several senders of
out-of-dialog requests were refactored as a result.

(closes issue ASTERISK-21084)
Review: https://reviewboard.asterisk.org/r/3050/
........

Merged revisions 405565 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@405566 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 250 insertions, 0 deletions

diff --git a/res/res_pjsip_path.c b/res/res_pjsip_path.c
new file mode 100644
index 000000000..28d8b589f
--- /dev/null
+++ b/res/res_pjsip_path.c
@@ -0,0 +1,250 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2013, Digium, Inc.
+ *
+ * Kinsey Moore <kmoore@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/res_pjsip_session.h"
+#include "asterisk/module.h"
+#include "asterisk/strings.h"
+
+static const pj_str_t PATH_NAME = { "Path", 4 };
+static pj_str_t PATH_SUPPORTED_NAME = { "path", 4 };
+
+static struct ast_sip_aor *find_aor(struct ast_sip_endpoint *endpoint, pjsip_uri *uri)
+{
+	char *configured_aors, *aor_name;
+	pjsip_sip_uri *sip_uri;
+	char *domain_name;
+	RAII_VAR(struct ast_str *, id, NULL, ast_free);
+
+	if (ast_strlen_zero(endpoint->aors)) {
+		return NULL;
+	}
+
+	sip_uri = pjsip_uri_get_uri(uri);
+	domain_name = ast_alloca(sip_uri->host.slen + 1);
+	ast_copy_pj_str(domain_name, &sip_uri->host, sip_uri->host.slen + 1);
+
+	configured_aors = ast_strdupa(endpoint->aors);
+
+	/* Iterate the configured AORs to see if the user or the user+domain match */
+	while ((aor_name = strsep(&configured_aors, ","))) {
+		struct ast_sip_domain_alias *alias = NULL;
+
+		if (!pj_strcmp2(&sip_uri->user, aor_name)) {
+			break;
+		}
+
+		if (!id && !(id = ast_str_create(sip_uri->user.slen + sip_uri->host.slen + 2))) {
+			return NULL;
+		}
+
+		ast_str_set(&id, 0, "%.*s@", (int)sip_uri->user.slen, sip_uri->user.ptr);
+		if ((alias = ast_sorcery_retrieve_by_id(ast_sip_get_sorcery(), "domain_alias", domain_name))) {
+			ast_str_append(&id, 0, "%s", alias->domain);
+			ao2_cleanup(alias);
+		} else {
+			ast_str_append(&id, 0, "%s", domain_name);
+		}
+
+		if (!strcmp(aor_name, ast_str_buffer(id))) {
+			ast_free(id);
+			break;
+		}
+	}
+
+	if (ast_strlen_zero(aor_name)) {
+		return NULL;
+	}
+
+	return ast_sip_location_retrieve_aor(aor_name);
+}
+
+/*!
+ * \brief Get the path string associated with this contact and tdata
+ *
+ * \param endpoint The endpoint from which to pull associated path data
+ * \param contact_uri The URI identifying the associated contact
+ * \param path_str The place to store the retrieved path information
+ *
+ * \retval zero on success
+ * \retval non-zero on failure or no available path information
+ */
+static int path_get_string(pj_pool_t *pool, struct ast_sip_contact *contact, pj_str_t *path_str)
+{
+	if (!contact || ast_strlen_zero(contact->path)) {
+		return -1;
+	}
+
+	*path_str = pj_strdup3(pool, contact->path);
+	return 0;
+}
+
+static int add_supported(pjsip_tx_data *tdata)
+{
+	pjsip_supported_hdr *hdr;
+
+	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) {
+			return -1;
+		}
+
+		pjsip_msg_add_hdr(tdata->msg, (pjsip_hdr *)hdr);
+	}
+
+	/* add on to the existing Supported header */
+	pj_strassign(&hdr->values[hdr->count++], &PATH_SUPPORTED_NAME);
+
+	return 0;
+}
+
+/*!
+ * \internal
+ * \brief Adds a Route header to an outgoing request if
+ * path information is available.
+ *
+ * \param endpoint The endpoint with which this request is associated
+ * \param contact The contact to which this request is being sent
+ * \param tdata The outbound request
+ */
+static void path_outgoing_request(struct ast_sip_endpoint *endpoint, struct ast_sip_contact *contact, pjsip_tx_data *tdata)
+{
+	RAII_VAR(struct ast_sip_aor *, aor, NULL, ao2_cleanup);
+
+	if (!endpoint) {
+		return;
+	}
+
+	aor = find_aor(endpoint, tdata->msg->line.req.uri);
+	if (!aor || !aor->support_path) {
+		return;
+	}
+
+	if (add_supported(tdata)) {
+		return;
+	}
+
+	if (contact && !ast_strlen_zero(contact->path)) {
+		ast_sip_set_outbound_proxy(tdata, contact->path);
+	}
+}
+
+static void path_session_outgoing_request(struct ast_sip_session *session, pjsip_tx_data *tdata)
+{
+	path_outgoing_request(session->endpoint, session->contact, tdata);
+}
+
+/*!
+ * \internal
+ * \brief Adds a path header to an outgoing 2XX response
+ *
+ * \param endpoint The endpoint to which the INVITE response is to be sent
+ * \param contact The contact to which the INVITE response is to be sent
+ * \param tdata The outbound INVITE response
+ */
+static void path_outgoing_response(struct ast_sip_endpoint *endpoint, struct ast_sip_contact *contact, pjsip_tx_data *tdata)
+{
+	struct pjsip_status_line status = tdata->msg->line.status;
+	pj_str_t path_dup;
+	pjsip_generic_string_hdr *path_hdr;
+	pjsip_contact_hdr *contact_hdr;
+	RAII_VAR(struct ast_sip_aor *, aor, NULL, ao2_cleanup);
+	pjsip_cseq_hdr *cseq = pjsip_msg_find_hdr(tdata->msg, PJSIP_H_CSEQ, NULL);
+	const pj_str_t REGISTER_METHOD = {"REGISTER", 8};
+
+	if (!endpoint
+		|| !pj_stristr(&REGISTER_METHOD, &cseq->method.name)
+		|| !PJSIP_IS_STATUS_IN_CLASS(status.code, 200)) {
+		return;
+	}
+
+	contact_hdr = pjsip_msg_find_hdr(tdata->msg, PJSIP_H_CONTACT, NULL);
+	if (!contact_hdr) {
+		return;
+	}
+
+	aor = find_aor(endpoint, contact_hdr->uri);
+	if (!aor || !aor->support_path || add_supported(tdata)
+		|| path_get_string(tdata->pool, contact, &path_dup)) {
+		return;
+	}
+
+	path_hdr = pjsip_generic_string_hdr_create(tdata->pool, &PATH_NAME, &path_dup);
+	if (!path_hdr) {
+		return;
+	}
+
+	pjsip_msg_add_hdr(tdata->msg, (pjsip_hdr*)path_hdr);
+}
+
+static void path_session_outgoing_response(struct ast_sip_session *session, pjsip_tx_data *tdata)
+{
+	path_outgoing_response(session->endpoint, session->contact, tdata);
+}
+
+static struct ast_sip_supplement path_supplement = {
+	.priority = AST_SIP_SUPPLEMENT_PRIORITY_CHANNEL - 100,
+	.outgoing_request = path_outgoing_request,
+	.outgoing_response = path_outgoing_response,
+};
+
+static struct ast_sip_session_supplement path_session_supplement = {
+	.priority = AST_SIP_SUPPLEMENT_PRIORITY_CHANNEL - 100,
+	.outgoing_request = path_session_outgoing_request,
+	.outgoing_response = path_session_outgoing_response,
+};
+
+static int load_module(void)
+{
+	if (ast_sip_register_supplement(&path_supplement)) {
+		return AST_MODULE_LOAD_DECLINE;
+	}
+
+	if (ast_sip_session_register_supplement(&path_session_supplement)) {
+		ast_sip_unregister_supplement(&path_supplement);
+		return AST_MODULE_LOAD_DECLINE;
+	}
+
+	return AST_MODULE_LOAD_SUCCESS;
+}
+
+static int unload_module(void)
+{
+	ast_sip_unregister_supplement(&path_supplement);
+	ast_sip_session_unregister_supplement(&path_session_supplement);
+	return 0;
+}
+
+AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "PJSIP Path Header Support",
+		.load = load_module,
+		.unload = unload_module,
+		.load_pri = AST_MODPRI_APP_DEPEND,
+);