pjsip/src/pjsua/pjsua_inv.c

/* $Id$ */
/* 
 * Copyright (C) 2003-2006 Benny Prijono <benny@prijono.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 
 */
#include "pjsua.h"
#include <pj/log.h>


/*
 * pjsua_inv.c
 *
 * Invite session specific functionalities.
 */

#define THIS_FILE   "pjsua_inv.c"


/**
 * Make outgoing call.
 */
pj_status_t pjsua_invite(const char *cstr_dest_uri,
			 struct pjsua_inv_data **p_inv_data)
{
    pj_str_t dest_uri;
    pjsip_dialog *dlg;
    pjmedia_sdp_session *offer;
    pjsip_inv_session *inv;
    struct pjsua_inv_data *inv_data;
    pjsip_tx_data *tdata;
    int med_sk_index = 0;
    pj_status_t status;

    /* Convert cstr_dest_uri to dest_uri */
    
    dest_uri = pj_str((char*)cstr_dest_uri);

    /* Find free socket. */
    for (med_sk_index=0; med_sk_index<PJSUA_MAX_CALLS; ++med_sk_index) {
	if (!pjsua.med_sock_use[med_sk_index])
	    break;
    }

    if (med_sk_index == PJSUA_MAX_CALLS) {
	PJ_LOG(3,(THIS_FILE, "Error: too many calls!"));
	return PJ_ETOOMANY;
    }

    pjsua.med_sock_use[med_sk_index] = 1;

    /* Create outgoing dialog: */

    status = pjsip_dlg_create_uac( pjsip_ua_instance(), &pjsua.local_uri,
				   &pjsua.contact_uri, &dest_uri, &dest_uri,
				   &dlg);
    if (status != PJ_SUCCESS) {
	pjsua_perror(THIS_FILE, "Dialog creation failed", status);
	return status;
    }

    /* Get media capability from media endpoint: */

    status = pjmedia_endpt_create_sdp( pjsua.med_endpt, dlg->pool,
				       1, &pjsua.med_sock_info[med_sk_index], 
				       &offer);
    if (status != PJ_SUCCESS) {
	pjsua_perror(THIS_FILE, "pjmedia unable to create SDP", status);
	goto on_error;
    }

    /* Create the INVITE session: */

    status = pjsip_inv_create_uac( dlg, offer, 0, &inv);
    if (status != PJ_SUCCESS) {
	pjsua_perror(THIS_FILE, "Invite session creation failed", status);
	goto on_error;
    }


    /* Create and associate our data in the session. */

    inv_data = pj_pool_zalloc( dlg->pool, sizeof(struct pjsua_inv_data));
    inv_data->inv = inv;
    inv_data->call_slot = med_sk_index;
    dlg->mod_data[pjsua.mod.id] = inv_data;
    inv->mod_data[pjsua.mod.id] = inv_data;


    /* Set dialog Route-Set: */

    if (!pj_list_empty(&pjsua.route_set))
	pjsip_dlg_set_route_set(dlg, &pjsua.route_set);


    /* Set credentials: */

    pjsip_auth_clt_set_credentials( &dlg->auth_sess, pjsua.cred_count, 
				    pjsua.cred_info);


    /* Create initial INVITE: */

    status = pjsip_inv_invite(inv, &tdata);
    if (status != PJ_SUCCESS) {
	pjsua_perror(THIS_FILE, "Unable to create initial INVITE request", 
		     status);
	goto on_error;
    }


    /* Send initial INVITE: */

    status = pjsip_inv_send_msg(inv, tdata, NULL);
    if (status != PJ_SUCCESS) {
	pjsua_perror(THIS_FILE, "Unable to send initial INVITE request", 
		     status);
	goto on_error;
    }

    /* Add invite session to the list. */
    
    pj_list_push_back(&pjsua.inv_list, inv_data);


    /* Done. */
    if (p_inv_data)
	*p_inv_data = inv_data;

    return PJ_SUCCESS;


on_error:

    PJ_TODO(DESTROY_DIALOG_ON_FAIL);
    pjsua.med_sock_use[med_sk_index] = 0;
    return status;
}


/**
 * Handle incoming INVITE request.
 */
pj_bool_t pjsua_inv_on_incoming(pjsip_rx_data *rdata)
{
    pjsip_dialog *dlg = pjsip_rdata_get_dlg(rdata);
    pjsip_transaction *tsx = pjsip_rdata_get_tsx(rdata);
    pjsip_msg *msg = rdata->msg_info.msg;
    pjsip_tx_data *response = NULL;
    unsigned options = 0;
    pjsip_inv_session *inv;
    struct pjsua_inv_data *inv_data;
    pjmedia_sdp_session *answer;
    int med_sk_index;
    pj_status_t status;

    /* Don't want to handle anything but INVITE */
    if (msg->line.req.method.id != PJSIP_INVITE_METHOD)
	return PJ_FALSE;

    /* Don't want to handle anything that's already associated with
     * existing dialog or transaction.
     */
    if (dlg || tsx)
	return PJ_FALSE;


    /* Verify that we can handle the request. */
    status = pjsip_inv_verify_request(rdata, &options, NULL, NULL,
				      pjsua.endpt, &response);
    if (status != PJ_SUCCESS) {

	/*
	 * No we can't handle the incoming INVITE request.
	 */

	if (response) {
	    pjsip_response_addr res_addr;

	    pjsip_get_response_addr(response->pool, rdata, &res_addr);
	    pjsip_endpt_send_response(pjsua.endpt, &res_addr, response, 
				      NULL, NULL);

	} else {

	    /* Respond with 500 (Internal Server Error) */
	    pjsip_endpt_respond_stateless(pjsua.endpt, rdata, 500, NULL,
					  NULL, NULL);
	}

	return PJ_TRUE;
    } 


    /*
     * Yes we can handle the incoming INVITE request.
     */

    /* Find free call slot. */
    for (med_sk_index=0; med_sk_index<PJSUA_MAX_CALLS; ++med_sk_index) {
	if (!pjsua.med_sock_use[med_sk_index])
	    break;
    }

    if (med_sk_index == PJSUA_MAX_CALLS) {
	pjsip_endpt_respond_stateless(pjsua.endpt, rdata, 
				      PJSIP_SC_BUSY_HERE, NULL,
				      NULL, NULL);
	return PJ_TRUE;
    }


    pjsua.med_sock_use[med_sk_index] = 1;

    /* Get media capability from media endpoint: */

    status = pjmedia_endpt_create_sdp( pjsua.med_endpt, rdata->tp_info.pool,
				       1, &pjsua.med_sock_info[med_sk_index], 
				       &answer );
    if (status != PJ_SUCCESS) {
	pjsip_endpt_respond_stateless(pjsua.endpt, rdata, 500, NULL,
				      NULL, NULL);

	/* Free call socket. */
	pjsua.med_sock_use[med_sk_index] = 0;
	return PJ_TRUE;
    }

    /* Create dialog: */

    status = pjsip_dlg_create_uas( pjsip_ua_instance(), rdata,
				   &pjsua.contact_uri, &dlg);
    if (status != PJ_SUCCESS) {
	pjsip_endpt_respond_stateless(pjsua.endpt, rdata, 500, NULL,
				      NULL, NULL);

	/* Free call socket. */
	pjsua.med_sock_use[med_sk_index] = 0;
	return PJ_TRUE;
    }


    /* Create invite session: */

    status = pjsip_inv_create_uas( dlg, rdata, answer, 0, &inv);
    if (status != PJ_SUCCESS) {

	pjsip_dlg_respond(dlg, rdata, 500, NULL);

	/* Free call socket. */
	pjsua.med_sock_use[med_sk_index] = 0;

	// TODO: Need to delete dialog
	return PJ_TRUE;
    }


    /* Create and attach pjsua data to the dialog: */

    inv_data = pj_pool_zalloc(dlg->pool, sizeof(struct pjsua_inv_data));
    inv_data->inv = inv;
    inv_data->call_slot = inv_data->call_slot = med_sk_index;
    dlg->mod_data[pjsua.mod.id] = inv_data;
    inv->mod_data[pjsua.mod.id] = inv_data;

    pj_list_push_back(&pjsua.inv_list, inv_data);


    /* Answer with 100 (using the dialog, not invite): */

    status = pjsip_dlg_create_response(dlg, rdata, 100, NULL, &response);
    if (status != PJ_SUCCESS) {
	
	pjsua_perror(THIS_FILE, "Unable to create 100 response", status);

	pjsip_dlg_respond(dlg, rdata, 500, NULL);

	/* Free call socket. */
	pjsua.med_sock_use[med_sk_index] = 0;

	// TODO: Need to delete dialog

    } else {
	status = pjsip_dlg_send_response(dlg, pjsip_rdata_get_tsx(rdata), 
					 response);
	if (status != PJ_SUCCESS)
	    pjsua_perror(THIS_FILE, "Unable to send 100 response", status);
    }

    PJ_LOG(3,(THIS_FILE,
	      "\nIncoming call!!\n"
	      "From: %.*s\n"
	      "To:   %.*s\n"
	      "(press 'a' to answer, 'h' to decline)",
	      (int)dlg->remote.info_str.slen,
	      dlg->remote.info_str.ptr,
	      (int)dlg->local.info_str.slen,
	      dlg->local.info_str.ptr));
    /* This INVITE request has been handled. */
    return PJ_TRUE;
}


/*
 * This callback receives notification from invite session when the
 * session state has changed.
 */
void pjsua_inv_on_state_changed(pjsip_inv_session *inv, pjsip_event *e)
{
    struct pjsua_inv_data *inv_data;

    inv_data = inv->dlg->mod_data[pjsua.mod.id];

    /* If this is an outgoing INVITE that was created because of
     * REFER/transfer, send NOTIFY to transferer.
     */
    if (inv_data && inv_data->xfer_sub && e->type==PJSIP_EVENT_TSX_STATE) 
    {
	int st_code = -1;
	pjsip_evsub_state ev_state = PJSIP_EVSUB_STATE_ACTIVE;
	

	switch (inv->state) {
	case PJSIP_INV_STATE_NULL:
	case PJSIP_INV_STATE_CALLING:
	    /* Do nothing */
	    break;

	case PJSIP_INV_STATE_EARLY:
	case PJSIP_INV_STATE_CONNECTING:
	    st_code = e->body.tsx_state.tsx->status_code;
	    ev_state = PJSIP_EVSUB_STATE_ACTIVE;
	    break;

	case PJSIP_INV_STATE_CONFIRMED:
	    /* When state is confirmed, send the final 200/OK and terminate
	     * subscription.
	     */
	    st_code = e->body.tsx_state.tsx->status_code;
	    ev_state = PJSIP_EVSUB_STATE_TERMINATED;
	    break;

	case PJSIP_INV_STATE_DISCONNECTED:
	    st_code = e->body.tsx_state.tsx->status_code;
	    ev_state = PJSIP_EVSUB_STATE_TERMINATED;
	    break;
	}

	if (st_code != -1) {
	    pjsip_tx_data *tdata;
	    pj_status_t status;

	    status = pjsip_xfer_notify( inv_data->xfer_sub,
					ev_state, st_code,
					NULL, &tdata);
	    if (status != PJ_SUCCESS) {
		pjsua_perror(THIS_FILE, "Unable to create NOTIFY", status);
	    } else {
		status = pjsip_xfer_send_request(inv_data->xfer_sub, tdata);
		if (status != PJ_SUCCESS) {
		    pjsua_perror(THIS_FILE, "Unable to send NOTIFY", status);
		}
	    }
	}
    }


    /* Destroy media session when invite session is disconnected. */
    if (inv->state == PJSIP_INV_STATE_DISCONNECTED) {

	pj_assert(inv_data != NULL);

	if (inv_data && inv_data->session) {
	    pjmedia_conf_remove_port(pjsua.mconf, inv_data->conf_slot);
	    pjmedia_session_destroy(inv_data->session);
	    pjsua.med_sock_use[inv_data->call_slot] = 0;
	    inv_data->session = NULL;

	    PJ_LOG(3,(THIS_FILE,"Media session is destroyed"));
	}

	if (inv_data) {

	    pj_list_erase(inv_data);

	}
    }

    pjsua_ui_inv_on_state_changed(inv, e);
}


/*
 * Callback called by event framework when the xfer subscription state
 * has changed.
 */
static void xfer_on_evsub_state( pjsip_evsub *sub, pjsip_event *event)
{
    
    PJ_UNUSED_ARG(event);

    /*
     * We're only interested when subscription is terminated, to 
     * clear the xfer_sub member of the inv_data.
     */
    if (pjsip_evsub_get_state(sub) == PJSIP_EVSUB_STATE_TERMINATED) {
	struct pjsua_inv_data *inv_data;

	inv_data = pjsip_evsub_get_mod_data(sub, pjsua.mod.id);
	if (!inv_data)
	    return;

	pjsip_evsub_set_mod_data(sub, pjsua.mod.id, NULL);
	inv_data->xfer_sub = NULL;

	PJ_LOG(3,(THIS_FILE, "Xfer subscription terminated"));
    }
}


/*
 * Follow transfer (REFER) request.
 */
static void on_call_transfered( pjsip_inv_session *inv,
			        pjsip_rx_data *rdata )
{
    pj_status_t status;
    pjsip_tx_data *tdata;
    struct pjsua_inv_data *inv_data;
    const pj_str_t str_refer_to = { "Refer-To", 8};
    pjsip_generic_string_hdr *refer_to;
    char *uri;
    struct pjsip_evsub_user xfer_cb;
    pjsip_evsub *sub;

    /* Find the Refer-To header */
    refer_to = (pjsip_generic_string_hdr*)
	pjsip_msg_find_hdr_by_name(rdata->msg_info.msg, &str_refer_to, NULL);

    if (refer_to == NULL) {
	/* Invalid Request.
	 * No Refer-To header!
	 */
	PJ_LOG(4,(THIS_FILE, "Received REFER without Refer-To header!"));
	pjsip_dlg_respond( inv->dlg, rdata, 400, NULL);
	return;
    }

    PJ_LOG(3,(THIS_FILE, "Call to %.*s is being transfered to %.*s",
	      (int)inv->dlg->remote.info_str.slen,
	      inv->dlg->remote.info_str.ptr,
	      (int)refer_to->hvalue.slen, 
	      refer_to->hvalue.ptr));

    /* Init callback */
    pj_memset(&xfer_cb, 0, sizeof(xfer_cb));
    xfer_cb.on_evsub_state = &xfer_on_evsub_state;

    /* Create transferee event subscription */
    status = pjsip_xfer_create_uas( inv->dlg, &xfer_cb, rdata, &sub);
    if (status != PJ_SUCCESS) {
	pjsua_perror(THIS_FILE, "Unable to create xfer uas", status);
	pjsip_dlg_respond( inv->dlg, rdata, 500, NULL);
	return;
    }

    /* Accept the REFER request, send 200 (OK). */
    pjsip_xfer_accept(sub, rdata, 200, NULL);

    /* Create initial NOTIFY request */
    status = pjsip_xfer_notify( sub, PJSIP_EVSUB_STATE_ACTIVE,
				100, NULL, &tdata);
    if (status != PJ_SUCCESS) {
	pjsua_perror(THIS_FILE, "Unable to create NOTIFY to REFER", status);
	return;
    }

    /* Send initial NOTIFY request */
    status = pjsip_xfer_send_request( sub, tdata);
    if (status != PJ_SUCCESS) {
	pjsua_perror(THIS_FILE, "Unable to send NOTIFY to REFER", status);
	return;
    }

    /* We're cheating here.
     * We need to get a null terminated string from a pj_str_t.
     * So grab the pointer from the hvalue and NULL terminate it, knowing
     * that the NULL position will be occupied by a newline. 
     */
    uri = refer_to->hvalue.ptr;
    uri[refer_to->hvalue.slen] = '\0';

    /* Now make the outgoing call. */
    status = pjsua_invite(uri, &inv_data);
    if (status != PJ_SUCCESS) {

	/* Notify xferer about the error */
	status = pjsip_xfer_notify(sub, PJSIP_EVSUB_STATE_TERMINATED,
				   500, NULL, &tdata);
	if (status != PJ_SUCCESS) {
	    pjsua_perror(THIS_FILE, "Unable to create NOTIFY to REFER", 
			  status);
	    return;
	}
	status = pjsip_xfer_send_request(sub, tdata);
	if (status != PJ_SUCCESS) {
	    pjsua_perror(THIS_FILE, "Unable to send NOTIFY to REFER", 
			  status);
	    return;
	}
	return;
    }

    /* Put the server subscription in inv_data.
     * Subsequent state changed in pjsua_inv_on_state_changed() will be
     * reported back to the server subscription.
     */
    inv_data->xfer_sub = sub;

    /* Put the invite_data in the subscription. */
    pjsip_evsub_set_mod_data(sub, pjsua.mod.id, inv_data);
}


/*
 * This callback is called when transaction state has changed in INVITE
 * session. We use this to trap incoming REFER request.
 */
void pjsua_inv_on_tsx_state_changed(pjsip_inv_session *inv,
				    pjsip_transaction *tsx,
				    pjsip_event *e)
{
    if (tsx->role==PJSIP_ROLE_UAS &&
	tsx->state==PJSIP_TSX_STATE_TRYING &&
	pjsip_method_cmp(&tsx->method, &pjsip_refer_method)==0)
    {
	/*
	 * Incoming REFER request.
	 */
	on_call_transfered(inv, e->body.tsx_state.src.rdata);
    }
}


/*
 * This callback is called by invite session framework when UAC session
 * has forked.
 */
void pjsua_inv_on_new_session(pjsip_inv_session *inv, pjsip_event *e)
{
    PJ_UNUSED_ARG(inv);
    PJ_UNUSED_ARG(e);

    PJ_TODO(HANDLE_FORKED_DIALOG);
}


/*
 * Create inactive SDP for call hold.
 */
static pj_status_t create_inactive_sdp(struct pjsua_inv_data *inv_session,
				       pjmedia_sdp_session **p_answer)
{
    pj_status_t status;
    pjmedia_sdp_conn *conn;
    pjmedia_sdp_attr *attr;
    pjmedia_sdp_session *sdp;

    /* Create new offer */
    status = pjmedia_endpt_create_sdp(pjsua.med_endpt, pjsua.pool, 1,
				      &pjsua.med_sock_info[inv_session->call_slot],
				      &sdp);
    if (status != PJ_SUCCESS) {
	pjsua_perror(THIS_FILE, "Unable to create local SDP", status);
	return status;
    }

    /* Get SDP media connection line */
    conn = sdp->media[0]->conn;
    if (!conn)
	conn = sdp->conn;

    /* Modify address */
    conn->addr = pj_str("0.0.0.0");

    /* Remove existing directions attributes */
    pjmedia_sdp_media_remove_all_attr(sdp->media[0], "sendrecv");
    pjmedia_sdp_media_remove_all_attr(sdp->media[0], "sendonly");
    pjmedia_sdp_media_remove_all_attr(sdp->media[0], "recvonly");
    pjmedia_sdp_media_remove_all_attr(sdp->media[0], "inactive");

    /* Add inactive attribute */
    attr = pjmedia_sdp_attr_create(pjsua.pool, "inactive", NULL);
    pjmedia_sdp_media_add_attr(sdp->media[0], attr);

    *p_answer = sdp;

    return status;
}

/*
 * Called when session received new offer.
 */
void pjsua_inv_on_rx_offer( pjsip_inv_session *inv,
			    const pjmedia_sdp_session *offer)
{
    struct pjsua_inv_data *inv_data;
    pjmedia_sdp_conn *conn;
    pjmedia_sdp_session *answer;
    pj_bool_t is_remote_active;
    pj_status_t status;

    inv_data = inv->dlg->mod_data[pjsua.mod.id];

    /*
     * See if remote is offering active media (i.e. not on-hold)
     */
    is_remote_active = PJ_TRUE;

    conn = offer->media[0]->conn;
    if (!conn)
	conn = offer->conn;

    if (pj_strcmp2(&conn->addr, "0.0.0.0")==0 ||
	pj_strcmp2(&conn->addr, "0")==0)
    {
	is_remote_active = PJ_FALSE;

    } 
    else if (pjmedia_sdp_media_find_attr2(offer->media[0], "inactive", NULL))
    {
	is_remote_active = PJ_FALSE;
    }

    PJ_LOG(4,(THIS_FILE, "Received SDP offer, remote media is %s",
	      (is_remote_active ? "active" : "inactive")));

    /* Supply candidate answer */
    if (is_remote_active) {
	status = pjmedia_endpt_create_sdp( pjsua.med_endpt, inv->pool, 1,
					   &pjsua.med_sock_info[inv_data->call_slot],
					   &answer);
    } else {
	status = create_inactive_sdp( inv_data, &answer );
    }

    if (status != PJ_SUCCESS) {
	pjsua_perror(THIS_FILE, "Unable to create local SDP", status);
	return;
    }

    status = pjsip_inv_set_sdp_answer(inv, answer);
    if (status != PJ_SUCCESS) {
	pjsua_perror(THIS_FILE, "Unable to set answer", status);
	return;
    }

}


/*
 * Callback to be called when SDP offer/answer negotiation has just completed
 * in the session. This function will start/update media if negotiation
 * has succeeded.
 */
void pjsua_inv_on_media_update(pjsip_inv_session *inv, pj_status_t status)
{
    struct pjsua_inv_data *inv_data;
    const pjmedia_sdp_session *local_sdp;
    const pjmedia_sdp_session *remote_sdp;
    pjmedia_port *media_port;
    pj_str_t port_name;
    char tmp[PJSIP_MAX_URL_SIZE];

    if (status != PJ_SUCCESS) {

	pjsua_perror(THIS_FILE, "SDP negotiation has failed", status);
	return;

    }

    /* Destroy existing media session, if any. */

    inv_data = inv->dlg->mod_data[pjsua.mod.id];
    if (inv_data && inv_data->session) {
	pjmedia_conf_remove_port(pjsua.mconf, inv_data->conf_slot);
	pjmedia_session_destroy(inv_data->session);
	pjsua.med_sock_use[inv_data->call_slot] = 0;
	inv_data->session = NULL;
    }

    /* Get local and remote SDP */

    status = pjmedia_sdp_neg_get_active_local(inv->neg, &local_sdp);
    if (status != PJ_SUCCESS) {
	pjsua_perror(THIS_FILE, 
		     "Unable to retrieve currently active local SDP", 
		     status);
	return;
    }


    status = pjmedia_sdp_neg_get_active_remote(inv->neg, &remote_sdp);
    if (status != PJ_SUCCESS) {
	pjsua_perror(THIS_FILE, 
		     "Unable to retrieve currently active remote SDP", 
		     status);
	return;
    }

    /* Create new media session. 
     * The media session is active immediately.
     */
    if (pjsua.null_audio)
	return;
    
    status = pjmedia_session_create( pjsua.med_endpt, 1, 
				     &pjsua.med_sock_info[inv_data->call_slot],
				     local_sdp, remote_sdp, 
				     inv_data,
				     &inv_data->session );
    if (status != PJ_SUCCESS) {
	pjsua_perror(THIS_FILE, "Unable to create media session", 
		     status);
	return;
    }


    /* Get the port interface of the first stream in the session.
     * We need the port interface to add to the conference bridge.
     */
    pjmedia_session_get_port(inv_data->session, 0, &media_port);


    /*
     * Add the call to conference bridge.
     */
    port_name.ptr = tmp;
    port_name.slen = pjsip_uri_print(PJSIP_URI_IN_REQ_URI,
				     inv_data->inv->dlg->remote.info->uri,
				     tmp, sizeof(tmp));
    if (port_name.slen < 1) {
	port_name = pj_str("call");
    }
    status = pjmedia_conf_add_port( pjsua.mconf, inv->pool,
				    media_port, 
				    &port_name,
				    &inv_data->conf_slot);
    if (status != PJ_SUCCESS) {
	pjsua_perror(THIS_FILE, "Unable to create conference slot", 
		     status);
	pjmedia_session_destroy(inv_data->session);
	inv_data->session = NULL;
	return;
    }

    /* Connect new call to the sound device port (port zero) in the
     * main conference bridge.
     */
    pjmedia_conf_connect_port( pjsua.mconf, 0, inv_data->conf_slot);
    pjmedia_conf_connect_port( pjsua.mconf, inv_data->conf_slot, 0);

    /* Done. */
    {
	struct pjmedia_session_info sess_info;
	char info[80];
	int info_len = 0;
	unsigned i;

	pjmedia_session_get_info(inv_data->session, &sess_info);
	for (i=0; i<sess_info.stream_cnt; ++i) {
	    int len;
	    const char *dir;
	    pjmedia_stream_info *strm_info = &sess_info.stream_info[i];

	    switch (strm_info->dir) {
	    case PJMEDIA_DIR_NONE:
		dir = "inactive";
		break;
	    case PJMEDIA_DIR_ENCODING:
		dir = "sendonly";
		break;
	    case PJMEDIA_DIR_DECODING:
		dir = "recvonly";
		break;
	    case PJMEDIA_DIR_ENCODING_DECODING:
		dir = "sendrecv";
		break;
	    default:
		dir = "unknown";
		break;
	    }
	    len = pj_ansi_sprintf( info+info_len,
				   ", stream #%d: %.*s (%s)", i,
				   (int)strm_info->fmt.encoding_name.slen,
				   (int)strm_info->fmt.encoding_name.ptr,
				   dir);
	    if (len > 0)
		info_len += len;
	}
	PJ_LOG(3,(THIS_FILE,"Media started%s", info));
    }
}


/*
 * Hangup call.
 */
void pjsua_inv_hangup(struct pjsua_inv_data *inv_session, int code)
{
    pj_status_t status;
    pjsip_tx_data *tdata;

    status = pjsip_inv_end_session(inv_session->inv, 
				   code, NULL, &tdata);
    if (status != PJ_SUCCESS) {
	pjsua_perror(THIS_FILE, 
		     "Failed to create end session message", 
		     status);
	return;
    }

    /* pjsip_inv_end_session may return PJ_SUCCESS with NULL 
     * as p_tdata when INVITE transaction has not been answered
     * with any provisional responses.
     */
    if (tdata == NULL)
	return;

    status = pjsip_inv_send_msg(inv_session->inv, tdata, NULL);
    if (status != PJ_SUCCESS) {
	pjsua_perror(THIS_FILE, 
		     "Failed to send end session message", 
		     status);
	return;
    }
}


/*
 * Put call on-Hold.
 */
void pjsua_inv_set_hold(struct pjsua_inv_data *inv_session)
{
    pjmedia_sdp_session *sdp;
    pjsip_inv_session *inv = inv_session->inv;
    pjsip_tx_data *tdata;
    pj_status_t status;

    if (inv->state != PJSIP_INV_STATE_CONFIRMED) {
	PJ_LOG(3,(THIS_FILE, "Can not hold call that is not confirmed"));
	return;
    }

    status = create_inactive_sdp(inv_session, &sdp);
    if (status != PJ_SUCCESS)
	return;

    /* Send re-INVITE with new offer */
    status = pjsip_inv_reinvite( inv_session->inv, NULL, sdp, &tdata);
    if (status != PJ_SUCCESS) {
	pjsua_perror(THIS_FILE, "Unable to create re-INVITE", status);
	return;
    }

    status = pjsip_inv_send_msg( inv_session->inv, tdata, NULL);
    if (status != PJ_SUCCESS) {
	pjsua_perror(THIS_FILE, "Unable to send re-INVITE", status);
	return;
    }
}


/*
 * re-INVITE.
 */
void pjsua_inv_reinvite(struct pjsua_inv_data *inv_session)
{
    pjmedia_sdp_session *sdp;
    pjsip_tx_data *tdata;
    pjsip_inv_session *inv = inv_session->inv;
    pj_status_t status;


    if (inv->state != PJSIP_INV_STATE_CONFIRMED) {
	PJ_LOG(3,(THIS_FILE, "Can not re-INVITE call that is not confirmed"));
	return;
    }

    /* Create SDP */
    status = pjmedia_endpt_create_sdp( pjsua.med_endpt, inv->pool, 1,
				       &pjsua.med_sock_info[inv_session->call_slot],
				       &sdp);
    if (status != PJ_SUCCESS) {
	pjsua_perror(THIS_FILE, "Unable to get SDP from media endpoint", status);
	return;
    }

    /* Send re-INVITE with new offer */
    status = pjsip_inv_reinvite( inv_session->inv, NULL, sdp, &tdata);
    if (status != PJ_SUCCESS) {
	pjsua_perror(THIS_FILE, "Unable to create re-INVITE", status);
	return;
    }

    status = pjsip_inv_send_msg( inv_session->inv, tdata, NULL);
    if (status != PJ_SUCCESS) {
	pjsua_perror(THIS_FILE, "Unable to send re-INVITE", status);
	return;
    }
}


/*
 * Transfer call.
 */
void pjsua_inv_xfer_call(struct pjsua_inv_data *inv_session,
			 const char *dest)
{
    pjsip_evsub *sub;
    pjsip_tx_data *tdata;
    pj_str_t tmp;
    pj_status_t status;
 
    
    /* Create xfer client subscription.
     * We're not interested in knowing the transfer result, so we
     * put NULL as the callback.
     */
    status = pjsip_xfer_create_uac(inv_session->inv->dlg, NULL, &sub);
    if (status != PJ_SUCCESS) {
	pjsua_perror(THIS_FILE, "Unable to create xfer", status);
	return;
    }

    /*
     * Create REFER request.
     */
    status = pjsip_xfer_initiate(sub, pj_cstr(&tmp, dest), &tdata);
    if (status != PJ_SUCCESS) {
	pjsua_perror(THIS_FILE, "Unable to create REFER request", status);
	return;
    }

    /* Send. */
    status = pjsip_xfer_send_request(sub, tdata);
    if (status != PJ_SUCCESS) {
	pjsua_perror(THIS_FILE, "Unable to send REFER request", status);
	return;
    }

    /* For simplicity (that's what this program is intended to be!), 
     * leave the original invite session as it is. More advanced application
     * may want to hold the INVITE, or terminate the invite, or whatever.
     */
}


/*
 * Terminate all calls.
 */
void pjsua_inv_shutdown()
{
    struct pjsua_inv_data *inv_data, *next;

    inv_data = pjsua.inv_list.next;
    while (inv_data != &pjsua.inv_list) {
	pjsip_tx_data *tdata;

	next = inv_data->next;

	if (pjsip_inv_end_session(inv_data->inv, 410, NULL, &tdata)==0) {
	    if (tdata)
		pjsip_inv_send_msg(inv_data->inv, tdata, NULL);
	}

	inv_data = next;
    }
}