chan_h323.c

/*
 * chan_h323.c
 *
 * OpenH323 Channel Driver for ASTERISK PBX.
 *			By Jeremy McNamara
 *                      For The NuFone Network 
 *
 * This code 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. 
 *
 */


#include <stdio.h>
#include <pthread.h>
#include <string.h>
#include <asterisk/lock.h>
#include <asterisk/logger.h>
#include <asterisk/channel.h>
#include <asterisk/channel_pvt.h>
#include <asterisk/config.h>
#include <asterisk/module.h>
#include <asterisk/pbx.h>
#include <asterisk/options.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 <sys/socket.h>
#include <net/if.h>
#include <errno.h>
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <netdb.h>
#include <sys/signal.h>
#include <netinet/ip.h>


#include "chan_h323.h"

/** String variables required by ASTERISK */
static char *type	= "H323";
static char *desc	= "The NuFone Network's Open H.323 Channel Driver";
static char *tdesc	= "The NuFone Network's Open H.323 Channel Driver";
static char *config = "h323.conf";

static char default_context[AST_MAX_EXTENSION];

/** H.323 configuration values */
static char gatekeeper[100];
static int	gatekeeper_disable = 1;
static int	gatekeeper_discover = 0;
static int  usingGk;
static int	port = 1720;
static int  gkroute = 0;

/* Just about everybody seems to support ulaw, so make it a nice default */
static int capability = AST_FORMAT_ULAW;

/* TOS flag */
static int tos = 0;

static int dtmfmode = H323_DTMF_RFC2833;

static char secret[50];

/** Private structure of a OpenH323 channel */
struct oh323_pvt {
	pthread_mutex_t lock;					/* Channel private lock */
	call_options_t calloptions;				/* Options to be used during call setup */
	int	alreadygone;						/* Whether or not we've already been destroyed by or peer */
	int needdestroy;						/* if we need to be destroyed */
	call_details_t cd;						/* Call details */
	struct ast_channel *owner;				/* Who owns us */
	int capability;							/* Special capability */
	int nonCodecCapability;
	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 username[81];						/* H.323 alias using this channel */
	char accountcode[256];					/* Account code */
	int amaflags;							/* AMA Flags */
	char callerid[80];						/* Caller*ID if available */
	struct ast_rtp *rtp;					/* RTP Session */
	int dtmfmode;
	struct ast_dsp *vad;					/* Used for in-band DTMF detection */
	struct oh323_pvt *next;					/* Next channel in list */
} *iflist = NULL;

static struct ast_user_list {
	struct oh323_user *users;
	pthread_mutex_t lock;
} userl = { NULL, AST_MUTEX_INITIALIZER };

static struct ast_peer_list {
	struct oh323_peer *peers;
	pthread_mutex_t lock;
} peerl = { NULL, AST_MUTEX_INITIALIZER };

static struct ast_alias_list {
	struct oh323_alias *aliases;
	pthread_mutex_t lock;
} aliasl = { NULL, AST_MUTEX_INITIALIZER };

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

/** Protect the interface list (of oh323_pvt's) */
static pthread_mutex_t iflock = AST_MUTEX_INITIALIZER;

/** Usage counter and associated lock */
static int usecnt =0;
static pthread_mutex_t usecnt_lock = AST_MUTEX_INITIALIZER;

/* Protect the monitoring thread, so only one process can kill or start it, and not
   when it's doing something critical. */
static pthread_mutex_t monlock = AST_MUTEX_INITIALIZER;

/* 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 = 0;

static int restart_monitor(void);

static void __oh323_destroy(struct oh323_pvt *p)
{
	struct oh323_pvt *cur, *prev = NULL;
	
	if (p->rtp) {
		ast_rtp_destroy(p->rtp);
	}
	
	/* Unlink us from the owner if we have one */
	if (p->owner) {
		ast_pthread_mutex_lock(&p->owner->lock);
		ast_log(LOG_DEBUG, "Detaching from %s\n", p->owner->name);
		p->owner->pvt->pvt = NULL;
		ast_pthread_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
		free(p);
}

static void oh323_destroy(struct oh323_pvt *p)
{
	ast_pthread_mutex_lock(&iflock);
	__oh323_destroy(p);
	ast_pthread_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);
			}
			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);
		
		/* set the usage flag to a sane starting value*/
		user->inUse = 0;
		/* Assume we can native bridge */
		user->bridge = 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, "noFastStart")) {
				user->noFastStart = ast_true(v->value);
			} else if (!strcasecmp(v->name, "noH245Tunneling")) {
				user->noH245Tunneling = ast_true(v->value);
			} else if (!strcasecmp(v->name, "noSilenceSuppression")) {
				user->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, "incominglimit")) {
				user->incominglimit = atoi(v->value);
				if (user->incominglimit < 0)
					user->incominglimit = 0;
			} else if (!strcasecmp(v->name, "host")) {
				if (!strcasecmp(v->value, "dynamic")) {
					ast_log(LOG_ERROR, "Dynamic host configuration not implemented, yet!\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;
	int found=0;
	
	prev = NULL;
	ast_pthread_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_pthread_mutex_unlock(&peerl.lock);
 	} else {
		ast_pthread_mutex_unlock(&peerl.lock);
		peer = malloc(sizeof(struct oh323_peer));
		memset(peer, 0, sizeof(struct oh323_peer));
	}
	if (peer) {
		if (!found) {
			strncpy(peer->name, name, sizeof(peer->name)-1);
		}
		
		/* set the usage flag to a sane starting value*/
		peer->inUse = 0;

		while(v) {
			if (!strcasecmp(v->name, "context")) {
				strncpy(peer->context, v->value, sizeof(peer->context)-1);
			}  else if (!strcasecmp(v->name, "bridge")) {
				peer->bridge = ast_true(v->value);
			} else if (!strcasecmp(v->name, "noFastStart")) {
				peer->noFastStart = ast_true(v->value);
			} else if (!strcasecmp(v->name, "noH245Tunneling")) {
				peer->noH245Tunneling = ast_true(v->value);
			} else if (!strcasecmp(v->name, "noSilenceSuppression")) {
				peer->noSilenceSuppression = ast_true(v->value);
			} else if (!strcasecmp(v->name, "outgoinglimit")) {
				peer->outgoinglimit = atoi(v->value);
				if (peer->outgoinglimit > 0)
					peer->outgoinglimit = 0;
			} else if (!strcasecmp(v->name, "host")) {
				if (!strcasecmp(v->value, "dynamic")) {
					ast_log(LOG_ERROR, "Dynamic host configuration not implemented, yet!\n");
					free(peer);
					return NULL;
				}
				if (ast_get_ip(&peer->addr, v->value)) {
						free(peer);
						return NULL;
				}
			} 
			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 = c->pvt->pvt;
	if (p && 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);
	return 0;
}


/**
 * Make a call over the specified channel to the specified 
 * destination. This function will parse the destination string
 * and determine the address-number to call.
 * Return -1 on error, 0 on success.
 */
static int oh323_call(struct ast_channel *c, char *dest, int timeout)
{
	int res;
	struct oh323_pvt *p = c->pvt->pvt;
	char called_addr[256];
	char *tmp;

	strtok_r(dest, "/", &(tmp));

	ast_log(LOG_DEBUG, "dest=%s, timeout=%d.\n", dest, timeout);

	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;
	}
	
	/* outgoing call */
	p->outgoing = 1;

	/* Clear the call token */
	if ((p->cd).call_token == NULL)
		(p->cd).call_token = (char *)malloc(128);

	memset((char *)(p->cd).call_token, 0, 128);
	
	if (p->cd.call_token == NULL) {
		ast_log(LOG_ERROR, "Not enough memory.\n");
		return -1;
	}

	/* Build the address to call */
	memset(called_addr, 0, sizeof(dest));
	memcpy(called_addr, dest, sizeof(called_addr));

	/* Copy callerid, if there is any */
	if (c->callerid) {
		char *tmp = strchr(c->callerid, '"');
		if (!tmp) {
			p->calloptions.callerid = malloc(80); // evil
			// sprintf(p->calloptions.callerid, "\"%s\"", c->callerid);
			sprintf(p->calloptions.callerid, "\"\" <%s>", c->callerid);
		} else {
			p->calloptions.callerid = strdup(c->callerid);
		}	
	 }

	res = h323_make_call(called_addr, &(p->cd), p->calloptions);

	if (res) {
		ast_log(LOG_NOTICE, "h323_make_call failed(%s)\n", c->name);
		return -1;
	}

	ast_setstate(c, AST_STATE_RINGING);
	return 0;
}


static int oh323_answer(struct ast_channel *c)
{
	int res;

	struct oh323_pvt *p = c->pvt->pvt;

	res = h323_answering_call(p->cd.call_token, 0);
	
	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 *p = c->pvt->pvt;
	int needcancel = 0;
	if (h323debug)
		ast_log(LOG_DEBUG, "oh323_hangup(%s)\n", c->name);
	if (!c->pvt->pvt) {
		ast_log(LOG_DEBUG, "Asked to hangup channel not connected\n");
		return 0;
	}
	ast_pthread_mutex_lock(&p->lock);
	/* Determine how to disconnect */
	if (p->owner != c) {
		ast_log(LOG_WARNING, "Huh?  We aren't the owner?\n");
		ast_pthread_mutex_unlock(&p->lock);
		return 0;
	}
	if (!c || (c->_state != AST_STATE_UP))
		needcancel = 1;
	/* Disconnect */
	p = c->pvt->pvt;
	
	/* Free dsp used for in-band DTMF detection */
	if (p->vad) {
		ast_dsp_free(p->vad);
     }

	p->owner = NULL;
	c->pvt->pvt = NULL;

	/* Start the process if it's not already started */
	if (!p->alreadygone) {
		if (h323_clear_call((p->cd).call_token)) 
			ast_log(LOG_DEBUG, "ClearCall failed.\n");
		p->needdestroy = 1;
	}

	/* Update usage counter */
	ast_pthread_mutex_lock(&usecnt_lock);
	usecnt--;
	if (usecnt < 0)
		ast_log(LOG_WARNING, "Usecnt < 0\n");
	ast_pthread_mutex_unlock(&usecnt_lock);
	ast_update_use_count();

	ast_pthread_mutex_unlock(&p->lock);
	return 0;
}

static struct ast_frame *oh323_rtp_read(struct oh323_pvt *p)
{
	/* Retrieve audio/etc from channel.  Assumes p->lock is already held. */
	struct ast_frame *f;
	static struct ast_frame null_frame = { AST_FRAME_NULL, };
	f = ast_rtp_read(p->rtp);
	/* Don't send RFC2833 if we're not supposed to */
	if (f && (f->frametype == AST_FRAME_DTMF) && !(p->dtmfmode & H323_DTMF_RFC2833))
		return &null_frame;
	if (p->owner) {
		/* We already hold the channel lock */
		if (f->frametype == AST_FRAME_VOICE) {
			if (f->subclass != p->owner->nativeformats) {
				ast_log(LOG_DEBUG, "Oooh, format changed to %d\n", f->subclass);
				p->owner->nativeformats = f->subclass;
				ast_set_read_format(p->owner, p->owner->readformat);
				ast_set_write_format(p->owner, p->owner->writeformat);
			}
		
			/* Do in-band DTMF detection */
			if (p->dtmfmode & H323_DTMF_INBAND) {
                   f = ast_dsp_process(p->owner,p->vad,f,0);
				   if (f->frametype == AST_FRAME_DTMF)
					ast_log(LOG_DEBUG, "Got 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 *p = c->pvt->pvt;
	ast_pthread_mutex_lock(&p->lock);
	fr = oh323_rtp_read(p);
	ast_pthread_mutex_unlock(&p->lock);
	return fr;
}

static int oh323_write(struct ast_channel *c, struct ast_frame *frame)
{
	struct oh323_pvt *p = c->pvt->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 -1;
		}
	}
	if (p) {
		ast_pthread_mutex_lock(&p->lock);
		if (p->rtp) {
			res =  ast_rtp_write(p->rtp, frame);
		}
		ast_pthread_mutex_unlock(&p->lock);
	}
	return res;
}

/** FIXME: Can I acutally use this or does Open H.323 take care of everything? */
static int oh323_indicate(struct ast_channel *c, int condition)
{

	struct oh323_pvt *p = c->pvt->pvt;
	
	switch(condition) {
	case AST_CONTROL_RINGING:
		if (c->_state == AST_STATE_RING) {
		//	transmit_response(p, "180 Ringing", &p->initreq);
			break;
		}
		return -1;
	case AST_CONTROL_BUSY:
		if (c->_state != AST_STATE_UP) {
		//	transmit_response(p, "600 Busy everywhere", &p->initreq);
			p->alreadygone = 1;
			ast_softhangup(c, AST_SOFTHANGUP_DEV);
			break;
		}
		return -1;
	case AST_CONTROL_CONGESTION:
		if (c->_state != AST_STATE_UP) {
		//	transmit_response(p, "486 Busy here", &p->initreq);
			p->alreadygone = 1;
			ast_softhangup(c, AST_SOFTHANGUP_DEV);
			break;
		}
		return -1;
	case -1:
		return -1;
	default:
		ast_log(LOG_WARNING, "Don't know how to indicate condition %d\n", condition);
		return -1;
	}
	return 0;
}

// FIXME: WTF is this? Do I need this???
static int oh323_fixup(struct ast_channel *oldchan, struct ast_channel *newchan)
{
	struct oh323_pvt *p = newchan->pvt->pvt;

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

static struct ast_channel *oh323_new(struct oh323_pvt *i, int state, const char *host)
{
	struct ast_channel *tmp;
	int fmt;
	tmp = ast_channel_alloc(1);
	
	if (tmp) {
		
		snprintf(tmp->name, sizeof(tmp->name)-1, "H323/%s", host);
		tmp->nativeformats = i->capability;
		if (!tmp->nativeformats)
			tmp->nativeformats = capability;
		fmt = ast_best_codec(tmp->nativeformats);
		tmp->type = type;
		tmp->fds[0] = ast_rtp_fd(i->rtp);
		ast_setstate(tmp, state);
		
		if (state == AST_STATE_RING)
			tmp->rings = 1;
		
		tmp->writeformat = fmt;
		tmp->pvt->rawwriteformat = fmt;
		tmp->readformat = fmt;
		tmp->pvt->rawreadformat = fmt;
		
		/* Allocate dsp for in-band DTMF support */
		if (i->dtmfmode & H323_DTMF_INBAND) {
			i->vad = ast_dsp_new();
			ast_dsp_set_features(i->vad, DSP_FEATURE_DTMF_DETECT);
        }

		/* Register the OpenH323 channel's functions. */
		tmp->pvt->pvt = i;
		tmp->pvt->send_digit = oh323_digit;
		tmp->pvt->call = oh323_call;
		tmp->pvt->hangup = oh323_hangup;
		tmp->pvt->answer = oh323_answer;
		tmp->pvt->read = oh323_read;
		tmp->pvt->write = oh323_write;
		tmp->pvt->indicate = oh323_indicate;
		tmp->pvt->fixup = oh323_fixup;
		tmp->pvt->bridge = ast_rtp_bridge;

		/*  Set the owner of this channel */
		i->owner = tmp;
		
		ast_pthread_mutex_lock(&usecnt_lock);
		usecnt++;
		ast_pthread_mutex_unlock(&usecnt_lock);
		ast_update_use_count();
		strncpy(tmp->context, i->context, sizeof(tmp->context)-1);
		strncpy(tmp->exten, i->exten, sizeof(tmp->exten)-1);		
		tmp->priority = 1;
		if (strlen(i->callerid))
			tmp->callerid = strdup(i->callerid);
		if (strlen(i->accountcode))
			strncpy(tmp->accountcode, i->accountcode, sizeof(tmp->accountcode)-1);
		if (i->amaflags)
			tmp->amaflags = i->amaflags;
		if (state != AST_STATE_DOWN) {
			if (ast_pbx_start(tmp)) {
				ast_log(LOG_WARNING, "Unable to start PBX on %s\n", tmp->name);
				ast_hangup(tmp);
				tmp = NULL;
			}
		}
	} else
		ast_log(LOG_WARNING, "Unable to allocate channel structure\n");
	return tmp;
}

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

	p = malloc(sizeof(struct oh323_pvt));
	if (!p) {
		ast_log(LOG_ERROR, "Couldn't allocate private structure. This is bad\n");
		return NULL;
	}

	/* Keep track of stuff */
	memset(p, 0, sizeof(struct oh323_pvt));
	p->rtp = ast_rtp_new(sched, io, 1, 0);

	if (!p->rtp) {
		ast_log(LOG_WARNING, "Unable to create RTP session: %s\n", strerror(errno));
		free(p);
		return NULL;
	}
	ast_rtp_settos(p->rtp, tos);
	ast_pthread_mutex_init(&p->lock);
	
	p->cd.call_reference = callid;
	p->bridge = 1;
	
	p->dtmfmode = dtmfmode;
	if (p->dtmfmode & H323_DTMF_RFC2833)
		p->nonCodecCapability |= AST_RTP_DTMF;

	/* Add to interface list */
	ast_pthread_mutex_lock(&iflock);
	p->next = iflist;
	iflist = p;
	ast_pthread_mutex_unlock(&iflock);
	return p;
}

static struct oh323_pvt *find_call(int call_reference)
{  
        struct oh323_pvt *p;

		ast_pthread_mutex_lock(&iflock);
        p = iflist; 

        while(p) {
                if (p->cd.call_reference == call_reference) {
                        /* Found the call */						
						ast_pthread_mutex_unlock(&iflock);
						return p;
                }
                p = p->next; 
        }
        ast_pthread_mutex_unlock(&iflock);
		return NULL;
        
}

static struct ast_channel *oh323_request(char *type, int format, void *data)
{

	int oldformat;
	struct oh323_pvt *p;
	struct ast_channel *tmpc = NULL;
	char *dest = data;
	char *ext, *host;
	char *h323id = NULL;
	char tmp[256];

	
	ast_log(LOG_DEBUG, "type=%s, format=%d, data=%s.\n", type, format, (char *)data);

	oldformat = format;
	format &= capability;
	if (!format) {
		ast_log(LOG_NOTICE, "Asked to get a channel of unsupported format '%d'\n", format);
		return NULL;
	}
	
	strncpy(tmp, dest, sizeof(tmp) - 1);
		
	host = strchr(tmp, '@');
	if (host) {
		*host = '\0';
		host++;
		ext = tmp;
	} else {
		host = tmp;
		ext = NULL;
	}

	strtok_r(host, "/", &(h323id));
		
	if (*h323id) {
		h323_set_id(h323id);
	}
		
	
	p = oh323_alloc(0);

	if (!p) {
		ast_log(LOG_WARNING, "Unable to build pvt data for '%s'\n", (char *)data);
		return NULL;
	}

	/* Assign a default capability */
	p->capability = capability;

	if (p->dtmfmode) {
		if (p->dtmfmode & H323_DTMF_RFC2833)
			p->nonCodecCapability |= AST_RTP_DTMF;
		else
			p->nonCodecCapability &= ~AST_RTP_DTMF;
	}


	ast_log(LOG_DEBUG, "Host: %s\tUsername: %s\n", host, p->username);

	if (ext)
		strncpy(p->username, ext, sizeof(p->username) - 1);
	tmpc = oh323_new(p, AST_STATE_DOWN, host);
	if (!tmpc)
		oh323_destroy(p);
	
	restart_monitor();
	
	return tmpc;
}

struct oh323_alias *find_alias(const char *source_aliases)
{
	struct oh323_alias *a;

	a = aliasl.aliases;

	while(a) {

		if (!strcasecmp(a->name, source_aliases)) {
			break;
		}
		a = a->next;
	}
	return a;
}

struct oh323_user *find_user(const char *source_aliases)
{
	struct oh323_user *u;

	u = userl.users;

	while(u) {

		if (!strcasecmp(u->name, source_aliases)) {
			break;
		}
		u = u->next;
	}
	return u;

}

struct oh323_peer *find_peer(char *dest_peer)
{
	struct oh323_peer *p;

	p = peerl.peers;

	while(p) {
		if (!strcasecmp(p->name, dest_peer)) {
			break;
		}
		p = p->next;
	}
	return p;

}

/**
  * Callback for sending digits from H.323 up to asterisk
  *
  */
int send_digit(unsigned call_reference, char digit)
{
	struct oh323_pvt *p;
	struct ast_frame f;

	ast_log(LOG_DEBUG, "Recieved Digit: %c\n", digit);
	p = find_call(call_reference);
	
	if (!p) {
		ast_log(LOG_ERROR, "Private structure not found in send_digit.\n");
		return -1;
	}
	memset(&f, 0, sizeof(f));
	f.frametype = AST_FRAME_DTMF;
    f.subclass = digit;
    f.datalen = 0;
    f.samples = 300;
	f.offset = 0;
	f.data = NULL;
    f.mallocd = 0;
    f.src = "SEND_DIGIT";
   	
	return ast_queue_frame(p->owner, &f, 1);	
}

/**
  * Call-back function that gets called when any H.323 connection is made
  *
  * Returns the local RTP port
  */
int create_connection(unsigned call_reference)
{	
	struct oh323_pvt *p;
	struct sockaddr_in us;

	p = find_call(call_reference);

	if (!p) {
		ast_log(LOG_ERROR, "Unable to allocate private structure, this is very bad.\n");
		return -1;
	}

	/* figure out our local RTP port and tell the H.323 stack about it*/
	ast_rtp_get_us(p->rtp, &us);
	return ntohs(us.sin_port);
}

/**
 *  Call-back function for incoming calls
 *
 *  Returns 1 on success
 */

int setup_incoming_call(call_details_t cd)
{
	
	struct oh323_pvt *p = NULL;
	struct ast_channel *c = NULL;
	struct oh323_user *user = NULL;
	struct oh323_alias *alias = NULL;

	/* allocate the call*/
	p = oh323_alloc(cd.call_reference);

	if (!p) {
		ast_log(LOG_ERROR, "Unable to allocate private structure, this is bad.\n");
		return 0;
	}

	/* Populate the call details in the private structure */
	p->cd.call_token = cd.call_token;
	p->cd.call_source_aliases = cd.call_source_aliases;
	p->cd.call_dest_alias = cd.call_dest_alias;
	p->cd.call_source_e164 = cd.call_source_e164;
	p->cd.call_dest_e164 = cd.call_dest_e164;

	if (h323debug) {
		printf("	== Setting up Call\n");
		printf("	   -- Calling party name:  %s\n", p->cd.call_source_aliases);
		printf("	   -- Calling party number:  %s\n", p->cd.call_source_e164);
		printf("	   -- Called  party name:  %s\n", p->cd.call_dest_alias);
		printf("	   -- Called  party number:  %s\n", p->cd.call_dest_e164);
	}

	/* Decide if we are allowing Gatekeeper routed calls*/
	if ((!strcasecmp(cd.sourceIp, gatekeeper)) && (gkroute == -1) && (usingGk == 1)) {
		
		if (strlen(cd.call_dest_e164)) {
			strncpy(p->exten, cd.call_dest_e164, sizeof(p->exten)-1);
			strncpy(p->context, default_context, sizeof(p->context)-1); 
		} else {
			alias = find_alias(cd.call_dest_alias);
		
			if (!alias) {
				ast_log(LOG_ERROR, "Call for %s rejected, alias not found\n", cd.call_dest_alias);
				return 0;
			}
			printf("Alias found: %s and %s\n", alias->name, alias->context);

			strncpy(p->exten, alias->name, sizeof(p->exten)-1);
			strncpy(p->context, alias->context, sizeof(p->context)-1);
		}

		sprintf(p->callerid, "%s <%s>", p->cd.call_source_aliases, p->cd.call_source_e164);

	} else { 
		/* Either this call is not from the Gatekeeper 
		   or we are not allowing gk routed calls */
		
		user  = find_user(cd.call_source_aliases);
		
		if (!user) {
			sprintf(p->callerid, "%s <%s>", p->cd.call_source_aliases, p->cd.call_source_e164); 
			if (strlen(p->cd.call_dest_e164)) {
				strncpy(p->exten, cd.call_dest_e164, sizeof(p->exten)-1);
			} else {
				strncpy(p->exten, cd.call_dest_alias, sizeof(p->exten)-1);		
			}
			if (!strlen(default_context)) {
				ast_log(LOG_ERROR, "Call from user '%s' rejected due to no default context\n", p->cd.call_source_aliases);
				return 0;
			}
			strncpy(p->context, default_context, sizeof(p->context)-1);
			ast_log(LOG_DEBUG, "Sending %s to context [%s]\n", cd.call_source_aliases, p->context);
		} else {
			if (user->host) {
				if (strcasecmp(cd.sourceIp, inet_ntoa(user->addr.sin_addr))){
					
					if(!strlen(default_context)) {
						ast_log(LOG_ERROR, "Call from user '%s' rejected due to non-matching IP address of '%s'\n", user->name, cd.sourceIp);
                		return 0;