pjsip: Support dual stack automatically.

This change adds support for dual stack automatically. No
configuration is required and the IP address and version
in the SIP messages and SDP will be automatically changed
based on the transport over which the message is being
sent. RTP usage has also been changed to listen on both
IPv4 and IPv6 simultaneously to allow media to flow, and
to allow ICE support on both simultaneously. This also
allows failover between IPv6 and IPv4 to work as expected.

ASTERISK-26309 #close

Change-Id: I235a421d8f9a326606d861b449fa6fe3a030572d

2 files changed, 317 insertions, 0 deletions

diff --git a/res/res_pjsip/include/res_pjsip_private.h b/res/res_pjsip/include/res_pjsip_private.h
index 04cd85408..11ad12c45 100644
--- a/res/res_pjsip/include/res_pjsip_private.h
+++ b/res/res_pjsip/include/res_pjsip_private.h
@@ -184,6 +184,14 @@ void ast_sip_destroy_global_headers(void);
 int ast_res_pjsip_init_options_handling(int reload);
 
 /*!
+ * \internal Initialize message IP updating handling.
+ *
+ * \retval 0 on success
+ * \retval other on failure
+ */
+int ast_res_pjsip_init_message_ip_updater(void);
+
+/*!
  * \internal
  * \brief Initialize transport storage for contacts.
  *
@@ -248,6 +256,12 @@ void ast_res_pjsip_cleanup_options_handling(void);
 
 /*!
  * \internal
+ * \brief Clean up res_pjsip message ip updating handling
+ */
+void ast_res_pjsip_cleanup_message_ip_updater(void);
+
+/*!
+ * \internal
  * \brief Get threadpool options
  */
 void sip_get_threadpool_options(struct ast_threadpool_options *threadpool_options);
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;
+}