asterisk/res/res_pjsip_rfc3329.c

/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2022, Commend International
 *
 * Maximilian Fridrich <m.fridrich@commend.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>
	<depend>res_pjsip_session</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/causes.h"
#include "asterisk/threadpool.h"

static void rfc3329_incoming_response(struct ast_sip_session *session, struct pjsip_rx_data *rdata)
{
	static const pj_str_t str_security_server = { "Security-Server", 15 };
	struct ast_sip_contact_status *contact_status = NULL;
	struct ast_sip_security_mechanism *mech;
	pjsip_generic_string_hdr *header;
	char buf[128];
	char *hdr_val;
	char *mechanism;

	if (!session || !session->endpoint || !session->endpoint->security_negotiation
		|| !session->contact || !(contact_status = ast_sip_get_contact_status(session->contact))) {
		return;
	}

	ao2_lock(contact_status);
	if (AST_VECTOR_SIZE(&contact_status->security_mechanisms)) {
		goto out;
	}

	header = pjsip_msg_find_hdr_by_name(rdata->msg_info.msg, &str_security_server, NULL);
	for (; header;
		header = pjsip_msg_find_hdr_by_name(rdata->msg_info.msg, &str_security_server, header->next)) {
		/* Parse Security-Server headers and add to contact status to use for future requests. */
		ast_copy_pj_str(buf, &header->hvalue, sizeof(buf));
		hdr_val = ast_skip_blanks(buf);

		while ((mechanism = ast_strsep(&hdr_val, ',', AST_STRSEP_ALL))) {
			if (!ast_sip_str_to_security_mechanism(&mech, mechanism)) {
				AST_VECTOR_APPEND(&contact_status->security_mechanisms, mech);
			}
		}
	}

out:
	ao2_unlock(contact_status);
	ao2_cleanup(contact_status);
}

static void add_outgoing_request_headers(struct ast_sip_endpoint *endpoint, struct ast_sip_contact *contact, struct pjsip_tx_data *tdata)
{
	static const pj_str_t security_verify = { "Security-Verify", 15 };
	struct pjsip_generic_string_hdr *hdr = NULL;
	struct ast_sip_contact_status *contact_status = NULL;

	if (endpoint->security_negotiation != AST_SIP_SECURITY_NEG_MEDIASEC) {
		return;
	}

	contact_status = ast_sip_get_contact_status(contact);
	hdr = pjsip_msg_find_hdr_by_name(tdata->msg, &security_verify, NULL);

	if (contact_status == NULL) {
		return;
	}

	ao2_lock(contact_status);
	if (AST_VECTOR_SIZE(&contact_status->security_mechanisms) && hdr == NULL) {
		/* Add Security-Verify headers (with q-value) */
		ast_sip_add_security_headers(&contact_status->security_mechanisms, "Security-Verify", 0, tdata);
	} else if (!hdr && AST_VECTOR_SIZE(&endpoint->security_mechanisms)) {
		/* Add Security-Client headers (no q-value) */
		ast_sip_add_security_headers(&endpoint->security_mechanisms, "Security-Client", 0, tdata);
	}
	ao2_unlock(contact_status);
	ast_sip_add_header(tdata, "Require", "mediasec");
	ast_sip_add_header(tdata, "Proxy-Require", "mediasec");

	ao2_cleanup(contact_status);
}

static void rfc3329_outgoing_request(struct ast_sip_session *session, struct pjsip_tx_data *tdata)
{
	if (session->contact == NULL) {
		return;
	}
	add_outgoing_request_headers(session->endpoint, session->contact, tdata);
}

static struct ast_sip_session_supplement rfc3329_supplement = {
	.incoming_response = rfc3329_incoming_response,
	.outgoing_request = rfc3329_outgoing_request,
};

static void rfc3329_options_request(struct ast_sip_endpoint *endpoint, struct ast_sip_contact *contact, struct pjsip_tx_data *tdata)
{
	add_outgoing_request_headers(endpoint, contact, tdata);
}

static struct ast_sip_supplement rfc3329_options_supplement = {
	.method = "OPTIONS",
	.outgoing_request = rfc3329_options_request,
};

static int load_module(void)
{
	ast_sip_session_register_supplement(&rfc3329_supplement);
	ast_sip_register_supplement(&rfc3329_options_supplement);
	return AST_MODULE_LOAD_SUCCESS;
}

static int unload_module(void)
{
	ast_sip_session_unregister_supplement(&rfc3329_supplement);
	return 0;
}

AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "PJSIP RFC 3329 Support (partial)",
	.support_level = AST_MODULE_SUPPORT_CORE,
	.load = load_module,
	.unload = unload_module,
	.load_pri = AST_MODPRI_APP_DEPEND,
	.requires = "res_pjsip,res_pjsip_session",
);