chan_h323.c

/*
 * chan_h323.c
 *
 * OpenH323 Channel Driver for ASTERISK PBX.
 *			By Jeremy McNamara
 *                      For The NuFone Network 
 *
 * chan_h323 has been derived from code created by
 *               Michael Manousos and Mark Spencer
 *
 * This file is part of the chan_h323 driver for Asterisk
 *
 * chan_h323 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. 
 *
 * chan_h323 is distributed 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., 675 Mass Ave, Cambridge, MA 02139, USA. 
 *
 * Version Info: $Id$
 */

#include <sys/socket.h>
#include <sys/signal.h>
#include <sys/param.h>
#if defined(BSD)
#ifndef IPTOS_MINCOST
#define IPTOS_MINCOST 0x02
#endif
#endif
#include <arpa/inet.h>
#include <net/if.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <unistd.h>
#include <stdlib.h>
#include <netdb.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#ifdef __cplusplus
extern "C" {
#endif   
#include <asterisk/lock.h>
#include <asterisk/logger.h>
#include <asterisk/channel.h>
#include <asterisk/config.h>
#include <asterisk/module.h>
#include <asterisk/pbx.h>
#include <asterisk/options.h>
#include <asterisk/utils.h>
#include <asterisk/lock.h>
#include <asterisk/sched.h>
#include <asterisk/io.h>
#include <asterisk/rtp.h>
#include <asterisk/acl.h>
#include <asterisk/callerid.h>
#include <asterisk/cli.h>
#include <asterisk/dsp.h>
#include <asterisk/causes.h>
#ifdef __cplusplus
}
#endif
#include "h323/chan_h323.h"

send_digit_cb on_send_digit; 
on_rtp_cb on_external_rtp_create; 
start_rtp_cb on_start_rtp_channel; 
setup_incoming_cb on_incoming_call;
setup_outbound_cb on_outgoing_call; 
chan_ringing_cb	on_chan_ringing;
con_established_cb on_connection_established;
clear_con_cb on_connection_cleared;
answer_call_cb on_answer_call;
progress_cb on_progress;
rfc2833_cb on_set_rfc2833_payload;
hangup_cb on_hangup;

/* global debug flag */
int h323debug;

/** Variables required by Asterisk */
static const char type[] = "H323";
static const char desc[] = "The NuFone Network's Open H.323 Channel Driver";
static const char tdesc[] = "The NuFone Network's Open H.323 Channel Driver";
static const char config[] = "h323.conf";
static char default_context[AST_MAX_EXTENSION] = "default";
static struct sockaddr_in bindaddr;

/** H.323 configuration values */
static int h323_signalling_port = 1720;
static char gatekeeper[100];
static int gatekeeper_disable = 1;
static int gatekeeper_discover = 0;
static int usingGk = 0;
static int gkroute = 0;
/* Assume we can native bridge by default */
static int bridging = 1;
/* Find user by alias (h.323 id) is default, alternative is the incomming call's source IP address*/
static int userbyalias = 1;
static int capability = AST_FORMAT_ULAW;
static int tos = 0;
static int dtmfmode = H323_DTMF_RFC2833;
static char secret[50];

static call_options_t global_options;

/** Private structure of a OpenH323 channel */
struct oh323_pvt {
	ast_mutex_t lock;					/* Channel private lock */
	call_options_t options;					/* Options to be used during call setup */
	int alreadygone;					/* Whether or not we've already been destroyed by our peer */
	int needdestroy;					/* if we need to be destroyed */
	call_details_t cd;					/* Call details */
	struct ast_channel *owner;				/* Who owns us */
	struct sockaddr_in sa;                  		/* Our peer */
        struct sockaddr_in redirip; 			        /* Where our RTP should be going if not to us */
	int capability;						/* audio capability */
	int nonCodecCapability;					/* non-audio capability */
	int outgoing;						/* Outgoing or incoming call? */
	int nat;						/* Are we talking to a NAT EP?*/
	int bridge;						/* Determine of we should native bridge or not*/
	char exten[AST_MAX_EXTENSION];				/* Requested extension */
	char context[AST_MAX_EXTENSION];			/* Context where to start */
	char accountcode[256];					/* Account code */
	char cid_num[80];					/* Caller*id number, if available */
	char cid_name[80];					/* Caller*id name, if available */
	char rdnis[80];						/* Referring DNIS, if available */
	int amaflags;						/* AMA Flags */
	struct ast_rtp *rtp;					/* RTP Session */
	int dtmfmode;						/* What DTMF Mode is being used */
	struct ast_dsp *vad;					/* Used for in-band DTMF detection */
	int nativeformats;					/* Codec formats supported by a channel */
	int needhangup;						/* Send hangup when Asterisk is ready */
	int hangupcause;					/* Hangup cause from OpenH323 layer */
	struct oh323_pvt *next;					/* Next channel in list */
} *iflist = NULL;

static struct ast_user_list {
	struct oh323_user *users;
	ast_mutex_t lock;
} userl;

static struct ast_peer_list {
	struct oh323_peer *peers;
	ast_mutex_t lock;
} peerl;

static struct ast_alias_list {
	struct oh323_alias *aliases;
	ast_mutex_t lock;
} aliasl;

/** Asterisk RTP stuff */
static struct sched_context *sched;
static struct io_context *io;

/** Protect the interface list (oh323_pvt) */
AST_MUTEX_DEFINE_STATIC(iflock);

/** Usage counter and associated lock */
static int usecnt = 0;
AST_MUTEX_DEFINE_STATIC(usecnt_lock);

/* Protect the monitoring thread, so only one process can kill or start it, and not
   when it's doing something critical. */
AST_MUTEX_DEFINE_STATIC(monlock);

/* Protect the H.323 capabilities list, to avoid more than one channel to set the capabilities simultaneaously in the h323 stack. */
AST_MUTEX_DEFINE_STATIC(caplock);

/* Protect the reload process */
AST_MUTEX_DEFINE_STATIC(h323_reload_lock);
static int h323_reloading = 0;

/* This is the thread for the monitor which checks for input on the channels
   which are not currently in use.  */
static pthread_t monitor_thread = AST_PTHREADT_NULL;
static int restart_monitor(void);
static int h323_do_reload(void);

static struct ast_channel *oh323_request(const char *type, int format, void *data, int *cause);
static int oh323_digit(struct ast_channel *c, char digit);
static int oh323_call(struct ast_channel *c, char *dest, int timeout);
static int oh323_hangup(struct ast_channel *c);
static int oh323_answer(struct ast_channel *c);
static struct ast_frame *oh323_read(struct ast_channel *c);
static int oh323_write(struct ast_channel *c, struct ast_frame *frame);
static int oh323_indicate(struct ast_channel *c, int condition);
static int oh323_fixup(struct ast_channel *oldchan, struct ast_channel *newchan);

static const struct ast_channel_tech oh323_tech = {
	.type = type,
	.description = tdesc,
	.capabilities = AST_FORMAT_ULAW,
	.properties = AST_CHAN_TP_WANTSJITTER,
	.requester = oh323_request,
	.send_digit = oh323_digit,
	.call = oh323_call,
	.hangup = oh323_hangup,
	.answer = oh323_answer,
	.read = oh323_read,
	.write = oh323_write,
	.indicate = oh323_indicate,
	.fixup = oh323_fixup,
	/* disable, for now */
#if 0
	.bridge = ast_rtp_bridge,
#endif
};

static void oh323_update_info(struct ast_channel *c)
{
	struct oh323_pvt *pvt = c->tech_pvt;

	ast_mutex_lock(&pvt->lock);
	if (c->nativeformats != pvt->nativeformats) {
		if (h323debug)
			ast_log(LOG_DEBUG, "Preparing %s for new native format\n", c->name);
		c->nativeformats = pvt->nativeformats;
		ast_set_read_format(c, c->readformat);
		ast_set_write_format(c, c->writeformat);
	}
	if (pvt->needhangup) {
		if (h323debug)
			ast_log(LOG_DEBUG, "Process pending hangup for %s\n", c->name);
		c->_softhangup |= AST_SOFTHANGUP_DEV;
		c->hangupcause = pvt->hangupcause;
		ast_queue_hangup(c);
		pvt->needhangup = 0;
	}
	ast_mutex_unlock(&pvt->lock);
}

static void cleanup_call_details(call_details_t *cd) 
{
        if (cd->call_token) {
                free(cd->call_token);
                cd->call_token = NULL;
        }
        if (cd->call_source_aliases) {
                free(cd->call_source_aliases);
                cd->call_source_aliases = NULL;
        }
        if (cd->call_dest_alias) {
                free(cd->call_dest_alias);
                cd->call_dest_alias = NULL;
	}
        if (cd->call_source_name) { 
                free(cd->call_source_name);
                cd->call_source_name = NULL;
        }
        if (cd->call_source_e164) {
                free(cd->call_source_e164);
                cd->call_source_e164 = NULL;
        }
        if (cd->call_dest_e164) {
                free(cd->call_dest_e164);
                cd->call_dest_e164 = NULL;
        }
        if (cd->sourceIp) {
                free(cd->sourceIp);
                cd->sourceIp = NULL;
        }
}

static void __oh323_destroy(struct oh323_pvt *p)
{
	struct oh323_pvt *cur, *prev = NULL;
	
	if (p->rtp) {
		ast_rtp_destroy(p->rtp);
	}
	
	/* Free dsp used for in-band DTMF detection */
	if (p->vad) {
		ast_dsp_free(p->vad);
	}
	cleanup_call_details(&p->cd);

	/* Unlink us from the owner if we have one */
	if (p->owner) {
		ast_mutex_lock(&p->owner->lock);
		ast_log(LOG_DEBUG, "Detaching from %s\n", p->owner->name);
		p->owner->tech_pvt = NULL;
		ast_mutex_unlock(&p->owner->lock);
	}
	cur = iflist;
	while(cur) {
		if (cur == p) {
			if (prev)
				prev->next = cur->next;
			else
				iflist = cur->next;
			break;
		}
		prev = cur;
		cur = cur->next;
	}
	if (!cur) {
		ast_log(LOG_WARNING, "%p is not in list?!?! \n", cur);
	} else {
                ast_mutex_destroy(&p->lock);
		free(p);
        }
}

static void oh323_destroy(struct oh323_pvt *p)
{
	ast_mutex_lock(&iflock);
	__oh323_destroy(p);
	ast_mutex_unlock(&iflock);
}

static struct oh323_alias *build_alias(char *name, struct ast_variable *v)
{
	struct oh323_alias *alias;

	alias = (struct oh323_alias *)malloc(sizeof(struct oh323_alias));
	if (alias) {
		memset(alias, 0, sizeof(struct oh323_alias));
		strncpy(alias->name, name, sizeof(alias->name) - 1);
		while (v) {
			if (!strcasecmp(v->name, "e164")) {
				strncpy(alias->e164,  v->value, sizeof(alias->e164) - 1);
			} else if (!strcasecmp(v->name, "prefix")) {
				strncpy(alias->prefix,  v->value, sizeof(alias->prefix) - 1);
			} else if (!strcasecmp(v->name, "context")) {
				strncpy(alias->context,  v->value, sizeof(alias->context) - 1);
			} else if (!strcasecmp(v->name, "secret")) {
				strncpy(alias->secret,  v->value, sizeof(alias->secret) - 1);
			} else {
				if (strcasecmp(v->value, "h323")) { 	
					ast_log(LOG_WARNING, "Keyword %s does not make sense in type=h323\n", v->value);
				}
			}
			v = v->next;
		}
	}
	return alias;
}

static struct oh323_user *build_user(char *name, struct ast_variable *v)
{
	struct oh323_user *user;
	int format;
	
	user = (struct oh323_user *)malloc(sizeof(struct oh323_user));
	if (user) {
		memset(user, 0, sizeof(struct oh323_user));
		strncpy(user->name, name, sizeof(user->name) - 1);
		user->options.dtmfcodec = 101;
		/* set a native brigding default value */
		user->bridge = bridging;
		/* and default context */
		strncpy(user->context, default_context, sizeof(user->context) - 1);
		while(v) {
			if (!strcasecmp(v->name, "context")) {
				strncpy(user->context, v->value, sizeof(user->context) - 1);
			} else if (!strcasecmp(v->name, "bridge")) {
				user->bridge = ast_true(v->value);
                      } else if (!strcasecmp(v->name, "nat")) {
                              user->nat = ast_true(v->value);
			} else if (!strcasecmp(v->name, "noFastStart")) {
				user->options.noFastStart = ast_true(v->value);
			} else if (!strcasecmp(v->name, "noH245Tunneling")) {
				user->options.noH245Tunneling = ast_true(v->value);
			} else if (!strcasecmp(v->name, "noSilenceSuppression")) {
				user->options.noSilenceSuppression = ast_true(v->value);
			} else if (!strcasecmp(v->name, "secret")) {
				strncpy(user->secret, v->value, sizeof(user->secret) - 1);
			} else if (!strcasecmp(v->name, "callerid")) {
				strncpy(user->callerid, v->value, sizeof(user->callerid) - 1);
			} else if (!strcasecmp(v->name, "accountcode")) {
				strncpy(user->accountcode, v->value, sizeof(user->accountcode) - 1);
			} else if (!strcasecmp(v->name, "progress_setup")) {
				int progress_setup = atoi(v->value);
				if ((progress_setup != 0) &&
				   (progress_setup != 1) &&
				   (progress_setup != 3) &&
				   (progress_setup != 8)) {
					ast_log(LOG_WARNING, "Invalid value %d for progress_setup at line %d, assuming 0\n", progress_setup, v->lineno);
					progress_setup = 0;
				}
				user->options.progress_setup = progress_setup;
			} else if (!strcasecmp(v->name, "progress_alert")) {
				int progress_alert = atoi(v->value);
				if ((progress_alert != 0) &&
				   (progress_alert != 8)) {
					ast_log(LOG_WARNING, "Invalud value %d for progress_alert at line %d, assuming 0\n", progress_alert, v->lineno);
					progress_alert = 0;
				}
				user->options.progress_alert = progress_alert;
			} else if (!strcasecmp(v->name, "progress_audio")) {
				user->options.progress_audio = ast_true(v->value);
			} else if (!strcasecmp(v->name, "dtmfcodec")) {
				user->options.dtmfcodec = atoi(v->value);
			} else if (!strcasecmp(v->name, "host")) {
				if (!strcasecmp(v->value, "dynamic")) {
					ast_log(LOG_ERROR, "A dynamic host on a type=user does not make any sense\n");
					free(user);
					return NULL;
				} else if (ast_get_ip(&user->addr, v->value)) {
					free(user);
					return NULL;
				} 
				/* Let us know we need to use ip authentication */
				user->host = 1;
			} else if (!strcasecmp(v->name, "amaflags")) {
				format = ast_cdr_amaflags2int(v->value);
				if (format < 0) {
					ast_log(LOG_WARNING, "Invalid AMA Flags: %s at line %d\n", v->value, v->lineno);
				} else {
					user->amaflags = format;
				}
			}
			v = v->next;
		}
	}
	return user;
}

static struct oh323_peer *build_peer(char *name, struct ast_variable *v)
{
	struct oh323_peer *peer;
	struct oh323_peer *prev;
	struct ast_ha *oldha = NULL;
	int found=0;
	int format;	

	prev = NULL;
	ast_mutex_lock(&peerl.lock);
	peer = peerl.peers;

	while(peer) {
		if (!strcasecmp(peer->name, name)) {	
			break;
		}
		prev = peer;
		peer = peer->next;
	}

	if (peer) {
		found++;
		/* Already in the list, remove it and it will be added back (or FREE'd) */
		if (prev) {
			prev->next = peer->next;
		} else {
			peerl.peers = peer->next;
		}
		ast_mutex_unlock(&peerl.lock);
 	} else {
		ast_mutex_unlock(&peerl.lock);
		peer = (struct oh323_peer*)malloc(sizeof(struct oh323_peer));
		if (peer)
			memset(peer, 0, sizeof(struct oh323_peer));
	}
	if (peer) {
		if (!found) {
			strncpy(peer->name, name, sizeof(peer->name) - 1);
			peer->addr.sin_port = htons(h323_signalling_port);
			peer->addr.sin_family = AF_INET;
		}
		oldha = peer->ha;
		peer->ha = NULL;
		peer->addr.sin_family = AF_INET;
		peer->capability = capability;
		peer->options.dtmfcodec = 101;
		peer->dtmfmode = H323_DTMF_RFC2833;

		while(v) {
			if (!strcasecmp(v->name, "bridge")) {
				peer->bridge = ast_true(v->value);
			} else if (!strcasecmp(v->name, "nat")) {
				peer->nat = ast_true(v->value);
			} else if (!strcasecmp(v->name, "noFastStart")) {
				peer->options.noFastStart = ast_true(v->value);
			} else if (!strcasecmp(v->name, "noH245Tunneling")) {
				peer->options.noH245Tunneling = ast_true(v->value);
			} else if (!strcasecmp(v->name, "noSilenceSuppression")) {
				peer->options.noSilenceSuppression = ast_true(v->value);
			} else if (!strcasecmp(v->name, "progress_setup")) {
				int progress_setup = atoi(v->value);
				if ((progress_setup != 0) &&
				   (progress_setup != 1) &&
				   (progress_setup != 3) &&
				   (progress_setup != 8)) {
					ast_log(LOG_WARNING, "Invalid value %d for progress_setup at line %d, assuming 0\n", progress_setup, v->lineno);
					progress_setup = 0;
				}
				peer->options.progress_setup = progress_setup;
			} else if (!strcasecmp(v->name, "progress_alert")) {
				int progress_alert = atoi(v->value);
				if ((progress_alert != 0) &&
				   (progress_alert != 8)) {
					ast_log(LOG_WARNING, "Invalid value %d for progress_alert at line %d, assuming 0\n", progress_alert, v->lineno);
					progress_alert = 0;
				}
				peer->options.progress_alert = progress_alert;
			} else if (!strcasecmp(v->name, "progress_audio")) {
				peer->options.progress_audio = ast_true(v->value);
			} else if (!strcasecmp(v->name, "dtmfcodec")) {
				peer->options.dtmfcodec = atoi(v->value);
			} else if (!strcasecmp(v->name, "dtmfmode")) {
				if (!strcasecmp(v->value, "inband")) {
					peer->dtmfmode = H323_DTMF_INBAND;
				} else if (!strcasecmp(v->value, "rfc2833")) {
					peer->dtmfmode = H323_DTMF_RFC2833;
				} else {
					ast_log(LOG_WARNING, "Unknown DTMF Mode %s, using RFC2833\n", v->value);
					peer->dtmfmode = H323_DTMF_RFC2833;
				}	
			} else if (!strcasecmp(v->name, "allow")) {
				format = ast_getformatbyname(v->value);
				if (format < 1) {
					ast_log(LOG_WARNING, "Cannot allow unknown format '%s'\n", v->value);
				} else {
					peer->capability |= format;
				}
			} else if (!strcasecmp(v->name, "disallow")) {
				format = ast_getformatbyname(v->value);
				if (format < 1) {
					ast_log(LOG_WARNING, "Cannot disallow unknown format '%s'\n", v->value);
				} else {
					peer->capability |= ~format;
				}
			} else if (!strcasecmp(v->name, "host")) {
				if (!strcasecmp(v->value, "dynamic")) {
					ast_log(LOG_ERROR, "Dynamic host configuration not implemented.\n");
					free(peer);
					return NULL;
				}
				if (ast_get_ip(&peer->addr, v->value)) {
						ast_log(LOG_ERROR, "Could not determine IP for %s\n", v->value);
						free(peer);
						return NULL;
				}
			} else if (!strcasecmp(v->name, "port")) {
				peer->addr.sin_port = htons(atoi(v->value));
			}
			v=v->next;
		}
	}
	return peer;
}

/**
 * Send (play) the specified digit to the channel.
 * 
 */
static int oh323_digit(struct ast_channel *c, char digit)
{
	struct oh323_pvt *p = (struct oh323_pvt *) c->tech_pvt;
	if (h323debug)
		ast_log(LOG_DEBUG, "Sending digit %c on %s\n", digit, c->name);
	if (!p)
		return -1;
	ast_mutex_lock(&p->lock);
	if (p->rtp && (p->dtmfmode & H323_DTMF_RFC2833)) {
		ast_rtp_senddigit(p->rtp, digit);
	}
	/* If in-band DTMF is desired, send that */
	if ((p->dtmfmode & H323_DTMF_INBAND)) {
		h323_send_tone(p->cd.call_token, digit);
	}
	ast_mutex_unlock(&p->lock);
	oh323_update_info(c);
	return 0;
}

/**
 * Make a call over the specified channel to the specified 
 * destination.
 * Returns -1 on error, 0 on success.
 */
static int oh323_call(struct ast_channel *c, char *dest, int timeout)
{  
        int res = 0;
        struct oh323_pvt *pvt = (struct oh323_pvt *)c->tech_pvt;
        char addr[INET_ADDRSTRLEN];
        char called_addr[1024];
  
  	if (h323debug) {
  		ast_log(LOG_DEBUG, "Calling to %s on %s\n", dest, c->name);
        }
	if ((c->_state != AST_STATE_DOWN) && (c->_state != AST_STATE_RESERVED)) {
                ast_log(LOG_WARNING, "Line is already in use (%s)\n", c->name);
                return -1;
        }
        if (usingGk) {
                pvt->options.port = h323_signalling_port;
                if (ast_strlen_zero(pvt->exten)) {
	               	strncpy(called_addr, dest, sizeof(called_addr));
                } else {
                        snprintf(called_addr, sizeof(called_addr), "%s@%s", pvt->exten, dest);
     		}
        } else {
                ast_inet_ntoa(addr, sizeof(addr), pvt->sa.sin_addr);
                pvt->options.port = htons(pvt->sa.sin_port);
                if (ast_strlen_zero(pvt->exten)) {
                        snprintf(called_addr, sizeof(called_addr), "%s:%d", addr, pvt->options.port);
                } else {
                        snprintf(called_addr, sizeof(called_addr), "%s@%s:%d", pvt->exten, addr, pvt->options.port);
		}
	}
	/* make sure null terminated */
	called_addr[sizeof(called_addr) - 1] = '\0'; 

	if (c->cid.cid_num) {
		strncpy(pvt->options.cid_num, c->cid.cid_num, sizeof(pvt->options.cid_num));
	}
	if (c->cid.cid_name) {
		strncpy(pvt->options.cid_name, c->cid.cid_name, sizeof(pvt->options.cid_name));
	}

	/* indicate that this is an outgoing call */
	pvt->outgoing = 1;

	ast_log(LOG_DEBUG, "Placing outgoing call to %s, %d\n", called_addr, pvt->options.dtmfcodec);
	res = h323_make_call(called_addr, &(pvt->cd), &pvt->options);
	if (res) {
		ast_log(LOG_NOTICE, "h323_make_call failed(%s)\n", c->name);
		return -1;
	}
	oh323_update_info(c);
	return 0;
}

static int oh323_answer(struct ast_channel *c)
{
	int res;
	struct oh323_pvt *pvt = (struct oh323_pvt *) c->tech_pvt;
	char *token;

	if (h323debug)
		ast_log(LOG_DEBUG, "Answering on %s\n", c->name);

	ast_mutex_lock(&pvt->lock);
	token = pvt->cd.call_token ? strdup(pvt->cd.call_token) : NULL;
	ast_mutex_unlock(&pvt->lock);
	res = h323_answering_call(token, 0);
	if (token)
		free(token);

	oh323_update_info(c);
	if (c->_state != AST_STATE_UP) {
		ast_setstate(c, AST_STATE_UP);
	}
	return res;
}

static int oh323_hangup(struct ast_channel *c)
{
	struct oh323_pvt *pvt = (struct oh323_pvt *) c->tech_pvt;
	int needcancel = 0;
	int q931cause = AST_CAUSE_NORMAL_CLEARING;
	char *call_token;


	if (h323debug)
		ast_log(LOG_DEBUG, "Hanging up call %s\n", c->name);

	if (!c->tech_pvt) {
		ast_log(LOG_DEBUG, "Asked to hangup channel not connected\n");
		return 0;
	}
	ast_mutex_lock(&pvt->lock);
	/* Determine how to disconnect */
	if (pvt->owner != c) {
		ast_log(LOG_WARNING, "Huh?  We aren't the owner?\n");
		ast_mutex_unlock(&pvt->lock);
		return 0;
	}
	if (!c || (c->_state != AST_STATE_UP)) {
		needcancel = 1;
	}
	
	pvt->owner = NULL;
	c->tech_pvt = NULL;

	if (c->hangupcause) {
		q931cause = c->hangupcause;
	} else {
		char *cause = pbx_builtin_getvar_helper(c, "DIALSTATUS");
		if (cause) {
			if (!strcmp(cause, "CONGESTION")) {
				q931cause = AST_CAUSE_NORMAL_CIRCUIT_CONGESTION;
			} else if (!strcmp(cause, "BUSY")) {
				q931cause = AST_CAUSE_USER_BUSY;
			} else if (!strcmp(cause, "CHANISUNVAIL")) {
				q931cause = AST_CAUSE_REQUESTED_CHAN_UNAVAIL;
			} else if (!strcmp(cause, "NOANSWER")) {
				q931cause = AST_CAUSE_NO_ANSWER;
			} else if (!strcmp(cause, "CANCEL")) {
				q931cause = AST_CAUSE_CALL_REJECTED;
			}
		}
	}

	/* Start the process if it's not already started */
	if (!pvt->alreadygone && !pvt->hangupcause) {
		call_token = pvt->cd.call_token ? strdup(pvt->cd.call_token) : NULL;
		if (call_token) {
			/* Release lock to eliminate deadlock */
			ast_mutex_unlock(&pvt->lock);
			if (h323_clear_call(call_token, q931cause)) { 
				ast_log(LOG_DEBUG, "ClearCall failed.\n");
			}
			free(call_token);
			ast_mutex_lock(&pvt->lock);
		}
	} 
	pvt->needdestroy = 1;

	/* Update usage counter */
	ast_mutex_lock(&usecnt_lock);
	usecnt--;
	if (usecnt < 0) {
		ast_log(LOG_WARNING, "Usecnt < 0\n");
	}
	ast_mutex_unlock(&usecnt_lock);
	ast_mutex_unlock(&pvt->lock);
	ast_update_use_count();
	return 0;
}

static struct ast_frame *oh323_rtp_read(struct oh323_pvt *pvt)
{
	/* Retrieve audio/etc from channel.  Assumes pvt->lock is already held. */
	struct ast_frame *f;
	static struct ast_frame null_frame = { AST_FRAME_NULL, };

      	/* Only apply it for the first packet, we just need the correct ip/port */
      	if (pvt->nat) {
        	ast_rtp_setnat(pvt->rtp,pvt->nat);
              	pvt->nat = 0;
      	}

	f = ast_rtp_read(pvt->rtp);
	/* Don't send RFC2833 if we're not supposed to */
	if (f && (f->frametype == AST_FRAME_DTMF) && !(pvt->dtmfmode & H323_DTMF_RFC2833)) {
		return &null_frame;
	}
	if (pvt->owner) {
		/* We already hold the channel lock */
		if (f->frametype == AST_FRAME_VOICE) {
			if (f->subclass != pvt->owner->nativeformats) {
				/* Try to avoid deadlock */
				if (ast_mutex_trylock(&pvt->owner->lock)) {
					ast_log(LOG_NOTICE, "Format changed but channel is locked. Ignoring frame...\n");
					return &null_frame;
				}
				ast_log(LOG_DEBUG, "Oooh, format changed to %d\n", f->subclass);
				pvt->owner->nativeformats = f->subclass;
				pvt->nativeformats = f->subclass;
				ast_set_read_format(pvt->owner, pvt->owner->readformat);
				ast_set_write_format(pvt->owner, pvt->owner->writeformat);
				ast_mutex_unlock(&pvt->owner->lock);
			}	
			/* Do in-band DTMF detection */
			if ((pvt->dtmfmode & H323_DTMF_INBAND) && pvt->vad) {
                   		f = ast_dsp_process(pvt->owner,pvt->vad,f);
				if (f &&(f->frametype == AST_FRAME_DTMF)) {
					ast_log(LOG_DEBUG, "Received in-band digit %c.\n", f->subclass);
            			}
			}
			
		}
	}
	return f;
}

static struct ast_frame  *oh323_read(struct ast_channel *c)
{
	struct ast_frame *fr;
	struct oh323_pvt *pvt = (struct oh323_pvt *)c->tech_pvt;
	ast_mutex_lock(&pvt->lock);
	oh323_update_info(c);
	fr = oh323_rtp_read(pvt);
	ast_mutex_unlock(&pvt->lock);
	return fr;
}

static int oh323_write(struct ast_channel *c, struct ast_frame *frame)
{
	struct oh323_pvt *pvt = (struct oh323_pvt *) c->tech_pvt;
	int res = 0;
	if (frame->frametype != AST_FRAME_VOICE) {
		if (frame->frametype == AST_FRAME_IMAGE) {
			return 0;
		} else {
			ast_log(LOG_WARNING, "Can't send %d type frames with H323 write\n", frame->frametype);
			return 0;
		}
	} else {
		if (!(frame->subclass & c->nativeformats)) {
			ast_log(LOG_WARNING, "Asked to transmit frame type %d, while native formats is %d (read/write = %d/%d)\n",
				frame->subclass, c->nativeformats, c->readformat, c->writeformat);
			return 0;
		}
	}
	if (pvt) {
		ast_mutex_lock(&pvt->lock);
		if (pvt->rtp) {
			res =  ast_rtp_write(pvt->rtp, frame);
		}
		ast_mutex_unlock(&pvt->lock);
	}
	return res;
}

static int oh323_indicate(struct ast_channel *c, int condition)
{

	struct oh323_pvt *pvt = (struct oh323_pvt *) c->tech_pvt;
	char *token = (char *)NULL;

	ast_mutex_lock(&pvt->lock);
	token = (pvt->cd.call_token ? strdup(pvt->cd.call_token) : NULL);
	ast_mutex_unlock(&pvt->lock);

	if (h323debug)
		ast_log(LOG_DEBUG, "OH323: Indicating %d on %s\n", condition, token);

	switch(condition) {
	case AST_CONTROL_RINGING:
		if (c->_state == AST_STATE_RING || c->_state == AST_STATE_RINGING) {
			h323_send_alerting(token);
 			break;
 		}
 		if (token)
 			free(token);
		return -1;
	case AST_CONTROL_PROGRESS:
		if (c->_state != AST_STATE_UP) {
			h323_send_progress(token);
			break;
		}
		if (token)
			free(token);
		return -1;

	case AST_CONTROL_BUSY:
		if (c->_state != AST_STATE_UP) {
			h323_answering_call(token, 1);
 			pvt->alreadygone = 1;
			ast_softhangup_nolock(c, AST_SOFTHANGUP_DEV);			
			break;
		}
		if (token)
			free(token);
		return -1;
	case AST_CONTROL_CONGESTION:
		if (c->_state != AST_STATE_UP) {
			h323_answering_call(token, 1);
			pvt->alreadygone = 1;
			ast_softhangup_nolock(c, AST_SOFTHANGUP_DEV);
			break;
		}
		if (token)
			free(token);
		return -1;
	case AST_CONTROL_PROCEEDING:
	case -1:
		if (token)
			free(token);
		return -1;
	default:
		ast_log(LOG_WARNING, "Don't know how to indicate condition %d on %s\n", condition, token);
		if (token)
			free(token);
		return -1;
	}

	if (h323debug)
		ast_log(LOG_DEBUG, "OH323: Indicated %d on %s\n", condition, token);
	if (token)
		free(token);
	oh323_update_info(c);

	return -1;
}

static int oh323_fixup(struct ast_channel *oldchan, struct ast_channel *newchan)
{
	struct oh323_pvt *pvt = (struct oh323_pvt *) newchan->tech_pvt;

	ast_mutex_lock(&pvt->lock);
	if (pvt->owner != oldchan) {
		ast_log(LOG_WARNING, "old channel wasn't %p but was %p\n", oldchan, pvt->owner);
		return -1;
	}
	pvt->owner = newchan;
	ast_mutex_unlock(&pvt->lock);
	return 0;
}

static struct ast_channel *oh323_new(struct oh323_pvt *pvt, int state, const char *host)
{
	struct ast_channel *ch;
	int fmt;
	
	/* Don't hold a oh323_pvt lock while we allocate a chanel */
	ast_mutex_unlock(&pvt->lock);
	ch = ast_channel_alloc(1);
	/* Update usage counter */
	ast_mutex_lock(&usecnt_lock);
	usecnt++;
	ast_mutex_unlock(&usecnt_lock);
	ast_update_use_count();
	ast_mutex_lock(&pvt->lock);
	if (ch) {
		ch->tech = &oh323_tech;
		snprintf(ch->name, sizeof(ch->name), "H323/%s", host);
		ch->nativeformats = pvt->capability;
		if (!ch->nativeformats) {
			ch->nativeformats = capability;
		}
		pvt->nativeformats = ch->nativeformats;
		fmt = ast_best_codec(ch->nativeformats);
		ch->type = type;
		ch->fds[0] = ast_rtp_fd(pvt->rtp);
		if (state == AST_STATE_RING) {
			ch->rings = 1;
		}
		ch->writeformat = fmt;
		ch->rawwriteformat = fmt;
		ch->readformat = fmt;
		ch->rawreadformat = fmt;
		/* Allocate dsp for in-band DTMF support */
		if (pvt->dtmfmode & H323_DTMF_INBAND) {
			pvt->vad = ast_dsp_new();
			ast_dsp_set_features(pvt->vad, DSP_FEATURE_DTMF_DETECT);
        	}
		/* Register channel functions. */
		ch->tech_pvt = pvt;
		/*  Set the owner of this channel */
		pvt->owner = ch;
		
		strncpy(ch->context, pvt->context, sizeof(ch->context) - 1);
		strncpy(ch->exten, pvt->exten, sizeof(ch->exten) - 1);		
		ch->priority = 1;
		if (!ast_strlen_zero(pvt->accountcode)) {
			strncpy(ch->accountcode, pvt->accountcode, sizeof(ch->accountcode) - 1);
		}
		if (pvt->amaflags) {
			ch->amaflags = pvt->amaflags;
		}
		if (!ast_strlen_zero(pvt->cid_num)) {
			ch->cid.cid_num = strdup(pvt->cid_num);
		} else if (pvt->cd.call_source_e164 && !ast_strlen_zero(pvt->cd.call_source_e164)) {
			ch->cid.cid_num = strdup(pvt->cd.call_source_e164);
		}
		if (!ast_strlen_zero(pvt->cid_name)) {
			ch->cid.cid_name = strdup(pvt->cid_name);
		} else if (pvt->cd.call_source_e164 && !ast_strlen_zero(pvt->cd.call_source_name)) {
			ch->cid.cid_name = strdup(pvt->cd.call_source_name);
		}
		if (!ast_strlen_zero(pvt->rdnis)) {
			ch->cid.cid_rdnis = strdup(pvt->rdnis);
		}
		if (!ast_strlen_zero(pvt->exten) && strcmp(pvt->exten, "s")) {
			ch->cid.cid_dnid = strdup(pvt->exten);
		}
		ast_setstate(ch, state);
		if (state != AST_STATE_DOWN) {
			if (ast_pbx_start(ch)) {
				ast_log(LOG_WARNING, "Unable to start PBX on %s\n", ch->name);
				ast_hangup(ch);
				ch = NULL;
			}
		}
	} else  {
		ast_log(LOG_WARNING, "Unable to allocate channel structure\n");
	}
	return ch;
}

static struct oh323_pvt *oh323_alloc(int callid)
{
	struct oh323_pvt *pvt;

	pvt = (struct oh323_pvt *) malloc(sizeof(struct oh323_pvt));
	if (!pvt) {
		ast_log(LOG_ERROR, "Couldn't allocate private structure. This is bad\n");
		return NULL;
	}
	memset(pvt, 0, sizeof(struct oh323_pvt));
	pvt->rtp = ast_rtp_new(sched, io, 1, 0);
	if (!pvt->rtp) {
		ast_log(LOG_WARNING, "Unable to create RTP session: %s\n", strerror(errno));
		free(pvt);