1 files changed, 303 insertions, 0 deletions

diff --git a/res/res_pjsip/pjsip_message_ip_updater.c b/res/res_pjsip/pjsip_message_ip_updater.c
new file mode 100644
index 000000000..7671ad0a7
--- /dev/null
+++ b/res/res_pjsip/pjsip_message_ip_updater.c
@@ -0,0 +1,303 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2014-2016, 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.
+ */
+
+#include "asterisk.h"
+
+#include <pjsip.h>
+#include <pjsip_ua.h>
+
+#include "asterisk/res_pjsip.h"
+#include "asterisk/res_pjsip_session.h"
+#include "include/res_pjsip_private.h"
+
+#define MOD_DATA_RESTRICTIONS "restrictions"
+
+static pj_status_t multihomed_on_tx_message(pjsip_tx_data *tdata);
+
+/*! \brief Outgoing message modification restrictions */
+struct multihomed_message_restrictions {
+	/*! \brief Disallow modification of the From domain */
+	unsigned int disallow_from_domain_modification;
+};
+
+static pjsip_module multihomed_module = {
+	.name = { "Multihomed Routing", 18 },
+	.id = -1,
+	.priority = PJSIP_MOD_PRIORITY_TSX_LAYER - 1,
+	.on_tx_request = multihomed_on_tx_message,
+	.on_tx_response = multihomed_on_tx_message,
+};
+
+/*! \brief Helper function to get (or allocate if not already present) restrictions on a message */
+static struct multihomed_message_restrictions *multihomed_get_restrictions(pjsip_tx_data *tdata)
+{
+	struct multihomed_message_restrictions *restrictions;
+
+	restrictions = ast_sip_mod_data_get(tdata->mod_data, multihomed_module.id, MOD_DATA_RESTRICTIONS);
+	if (restrictions) {
+		return restrictions;
+	}
+
+	restrictions = PJ_POOL_ALLOC_T(tdata->pool, struct multihomed_message_restrictions);
+	ast_sip_mod_data_set(tdata->pool, tdata->mod_data, multihomed_module.id, MOD_DATA_RESTRICTIONS, restrictions);
+
+	return restrictions;
+}
+
+/*! \brief Callback invoked on non-session outgoing messages */
+static void multihomed_outgoing_message(struct ast_sip_endpoint *endpoint, struct ast_sip_contact *contact, struct pjsip_tx_data *tdata)
+{
+	struct multihomed_message_restrictions *restrictions = multihomed_get_restrictions(tdata);
+
+	restrictions->disallow_from_domain_modification = !ast_strlen_zero(endpoint->fromdomain);
+}
+
+/*! \brief PJSIP Supplement for tagging messages with restrictions */
+static struct ast_sip_supplement multihomed_supplement = {
+	.priority = AST_SIP_SUPPLEMENT_PRIORITY_FIRST,
+	.outgoing_request = multihomed_outgoing_message,
+	.outgoing_response = multihomed_outgoing_message,
+};
+
+/*! \brief Callback invoked on session outgoing messages */
+static void multihomed_session_outgoing_message(struct ast_sip_session *session, struct pjsip_tx_data *tdata)
+{
+	struct multihomed_message_restrictions *restrictions = multihomed_get_restrictions(tdata);
+
+	restrictions->disallow_from_domain_modification = !ast_strlen_zero(session->endpoint->fromdomain);
+}
+
+/*! \brief PJSIP Session Supplement for tagging messages with restrictions */
+static struct ast_sip_session_supplement multihomed_session_supplement = {
+	.priority = 1,
+	.outgoing_request = multihomed_session_outgoing_message,
+	.outgoing_response = multihomed_session_outgoing_message,
+};
+
+/*! \brief Helper function which returns a UDP transport bound to the given address and port */
+static pjsip_transport *multihomed_get_udp_transport(pj_str_t *address, int port)
+{
+	struct ao2_container *transport_states = ast_sip_get_transport_states();
+	struct ast_sip_transport_state *transport_state;
+	struct ao2_iterator iter;
+	pjsip_transport *sip_transport = NULL;
+
+	if (!transport_states) {
+		return NULL;
+	}
+
+	for (iter = ao2_iterator_init(transport_states, 0); (transport_state = ao2_iterator_next(&iter)); ao2_ref(transport_state, -1)) {
+		if (transport_state && ((transport_state->type != AST_TRANSPORT_UDP) ||
+			(pj_strcmp(&transport_state->transport->local_name.host, address)) ||
+			(transport_state->transport->local_name.port != port))) {
+			continue;
+		}
+
+		sip_transport = transport_state->transport;
+		break;
+	}
+	ao2_iterator_destroy(&iter);
+
+	ao2_ref(transport_states, -1);
+
+	return sip_transport;
+}
+
+/*! \brief Helper function which determines if a transport is bound to any */
+static int multihomed_bound_any(pjsip_transport *transport)
+{
+	pj_uint32_t loop6[4] = {0, 0, 0, 0};
+
+	if ((transport->local_addr.addr.sa_family == pj_AF_INET() &&
+		transport->local_addr.ipv4.sin_addr.s_addr == PJ_INADDR_ANY) ||
+		(transport->local_addr.addr.sa_family == pj_AF_INET6() &&
+		!pj_memcmp(&transport->local_addr.ipv6.sin6_addr, loop6, sizeof(loop6)))) {
+		return 1;
+	}
+
+	return 0;
+}
+
+/*! \brief Helper function which determines if the address within SDP should be rewritten */
+static int multihomed_rewrite_sdp(struct pjmedia_sdp_session *sdp)
+{
+	if (!sdp->conn) {
+		return 0;
+	}
+
+	/* If the host address is used in the SDP replace it with the address of what this is going out on */
+	if ((!pj_strcmp2(&sdp->conn->addr_type, "IP4") && !pj_strcmp2(&sdp->conn->addr,
+		ast_sip_get_host_ip_string(pj_AF_INET()))) ||
+		(!pj_strcmp2(&sdp->conn->addr_type, "IP6") && !pj_strcmp2(&sdp->conn->addr,
+		ast_sip_get_host_ip_string(pj_AF_INET6())))) {
+		return 1;
+	}
+
+	return 0;
+}
+
+static pj_status_t multihomed_on_tx_message(pjsip_tx_data *tdata)
+{
+	struct multihomed_message_restrictions *restrictions = ast_sip_mod_data_get(tdata->mod_data, multihomed_module.id, MOD_DATA_RESTRICTIONS);
+	pjsip_tpmgr_fla2_param prm;
+	pjsip_cseq_hdr *cseq;
+	pjsip_via_hdr *via;
+	pjsip_fromto_hdr *from;
+
+	/* Use the destination information to determine what local interface this message will go out on */
+	pjsip_tpmgr_fla2_param_default(&prm);
+	prm.tp_type = tdata->tp_info.transport->key.type;
+	pj_strset2(&prm.dst_host, tdata->tp_info.dst_name);
+	prm.local_if = PJ_TRUE;
+
+	/* If we can't get the local address use best effort and let it pass */
+	if (pjsip_tpmgr_find_local_addr2(pjsip_endpt_get_tpmgr(ast_sip_get_pjsip_endpoint()), tdata->pool, &prm) != PJ_SUCCESS) {
+		return PJ_SUCCESS;
+	}
+
+	/* For UDP we can have multiple transports so the port needs to be maintained */
+	if (tdata->tp_info.transport->key.type == PJSIP_TRANSPORT_UDP ||
+		tdata->tp_info.transport->key.type == PJSIP_TRANSPORT_UDP6) {
+		prm.ret_port = tdata->tp_info.transport->local_name.port;
+	}
+
+	/* If the IP source differs from the existing transport see if we need to update it */
+	if (pj_strcmp(&prm.ret_addr, &tdata->tp_info.transport->local_name.host)) {
+
+		/* If the transport it is going out on is different reflect it in the message */
+		if (tdata->tp_info.transport->key.type == PJSIP_TRANSPORT_UDP ||
+			tdata->tp_info.transport->key.type == PJSIP_TRANSPORT_UDP6) {
+			pjsip_transport *transport;
+
+			transport = multihomed_get_udp_transport(&prm.ret_addr, prm.ret_port);
+
+			if (transport) {
+				tdata->tp_info.transport = transport;
+			}
+		}
+
+		/* If the chosen transport is not bound to any we can't use the source address as it won't get back to us */
+		if (!multihomed_bound_any(tdata->tp_info.transport)) {
+			pj_strassign(&prm.ret_addr, &tdata->tp_info.transport->local_name.host);
+		}
+	} else {
+		/* The transport chosen will deliver this but ensure it is updated with the right information */
+		pj_strassign(&prm.ret_addr, &tdata->tp_info.transport->local_name.host);
+	}
+
+	/* If the message needs to be updated with new address do so */
+	if (tdata->msg->type == PJSIP_REQUEST_MSG || !(cseq = pjsip_msg_find_hdr(tdata->msg, PJSIP_H_CSEQ, NULL)) ||
+		pj_strcmp2(&cseq->method.name, "REGISTER")) {
+		pjsip_contact_hdr *contact = pjsip_msg_find_hdr(tdata->msg, PJSIP_H_CONTACT, NULL);
+		if (contact && (PJSIP_URI_SCHEME_IS_SIP(contact->uri) || PJSIP_URI_SCHEME_IS_SIPS(contact->uri))
+			&& !(tdata->msg->type == PJSIP_RESPONSE_MSG && tdata->msg->line.status.code / 100 == 3)) {
+			pjsip_sip_uri *uri = pjsip_uri_get_uri(contact->uri);
+
+			/* prm.ret_addr is allocated from the tdata pool OR the transport so it is perfectly fine to just do an assignment like this */
+			pj_strassign(&uri->host, &prm.ret_addr);
+			uri->port = prm.ret_port;
+			ast_debug(4, "Re-wrote Contact URI host/port to %.*s:%d\n",
+				(int)pj_strlen(&uri->host), pj_strbuf(&uri->host), uri->port);
+
+			if (tdata->tp_info.transport->key.type == PJSIP_TRANSPORT_UDP ||
+				tdata->tp_info.transport->key.type == PJSIP_TRANSPORT_UDP6) {
+				uri->transport_param.slen = 0;
+			} else {
+				pj_strdup2(tdata->pool, &uri->transport_param, pjsip_transport_get_type_name(tdata->tp_info.transport->key.type));
+			}
+
+			pjsip_tx_data_invalidate_msg(tdata);
+		}
+	}
+
+	if (tdata->msg->type == PJSIP_REQUEST_MSG && (via = pjsip_msg_find_hdr(tdata->msg, PJSIP_H_VIA, NULL))) {
+		pj_strassign(&via->sent_by.host, &prm.ret_addr);
+		via->sent_by.port = prm.ret_port;
+
+		pjsip_tx_data_invalidate_msg(tdata);
+	}
+
+	if (tdata->msg->type == PJSIP_REQUEST_MSG && (from = pjsip_msg_find_hdr(tdata->msg, PJSIP_H_FROM, NULL)) &&
+		(restrictions && !restrictions->disallow_from_domain_modification)) {
+		pjsip_name_addr *id_name_addr = (pjsip_name_addr *)from->uri;
+		pjsip_sip_uri *uri = pjsip_uri_get_uri(id_name_addr);
+		pj_sockaddr ip;
+
+		if (pj_strcmp2(&uri->host, "localhost") && pj_sockaddr_parse(pj_AF_UNSPEC(), 0, &uri->host, &ip) == PJ_SUCCESS) {
+			pj_strassign(&uri->host, &prm.ret_addr);
+			pjsip_tx_data_invalidate_msg(tdata);
+		}
+	}
+
+	/* Update the SDP if it is present */
+	if (tdata->msg->body && ast_sip_is_content_type(&tdata->msg->body->content_type, "application", "sdp") &&
+		multihomed_rewrite_sdp(tdata->msg->body->data)) {
+		struct pjmedia_sdp_session *sdp = tdata->msg->body->data;
+		static const pj_str_t STR_IP4 = { "IP4", 3 };
+		static const pj_str_t STR_IP6 = { "IP6", 3 };
+		pj_str_t STR_IP;
+		int stream;
+
+		STR_IP = tdata->tp_info.transport->key.type & PJSIP_TRANSPORT_IPV6 ? STR_IP6 : STR_IP4;
+
+		pj_strassign(&sdp->origin.addr, &prm.ret_addr);
+		sdp->origin.addr_type = STR_IP;
+		pj_strassign(&sdp->conn->addr, &prm.ret_addr);
+		sdp->conn->addr_type = STR_IP;
+
+		for (stream = 0; stream < sdp->media_count; ++stream) {
+			if (sdp->media[stream]->conn) {
+				pj_strassign(&sdp->media[stream]->conn->addr, &prm.ret_addr);
+				sdp->media[stream]->conn->addr_type = STR_IP;
+			}
+		}
+
+		pjsip_tx_data_invalidate_msg(tdata);
+	}
+
+	return PJ_SUCCESS;
+}
+
+void ast_res_pjsip_cleanup_message_ip_updater(void)
+{
+	ast_sip_unregister_service(&multihomed_module);
+	ast_sip_unregister_supplement(&multihomed_supplement);
+	ast_sip_session_unregister_supplement(&multihomed_session_supplement);
+}
+
+int ast_res_pjsip_init_message_ip_updater(void)
+{
+	if (ast_sip_session_register_supplement(&multihomed_session_supplement)) {
+		ast_log(LOG_ERROR, "Could not register multihomed session supplement for outgoing requests\n");
+		return -1;
+	}
+
+	if (ast_sip_register_supplement(&multihomed_supplement)) {
+		ast_log(LOG_ERROR, "Could not register multihomed supplement for outgoing requests\n");
+		ast_res_pjsip_cleanup_message_ip_updater();
+		return -1;
+	}
+
+	if (ast_sip_register_service(&multihomed_module)) {
+		ast_log(LOG_ERROR, "Could not register multihomed module for incoming and outgoing requests\n");
+		ast_res_pjsip_cleanup_message_ip_updater();
+		return -1;
+	}
+
+	return 0;
+}