q931.c

This a software PBX driver

	q931_call *cur, *prev;
	prev = NULL;
	cur = *pri->callpool;
	while(cur) {
		if ((c && (cur == c)) || (!c && (cur->cr == cr))) {
			if (prev)
				prev->next = cur->next;
			else
				*pri->callpool = cur->next;
			if (pri->debug & PRI_DEBUG_Q931_STATE)
				pri_message("NEW_HANGUP DEBUG: Destroying the call, ourstate %s, peerstate %s\n",callstate2str(cur->ourcallstate),callstate2str(cur->peercallstate));
			if (cur->retranstimer)
				pri_schedule_del(pri, cur->retranstimer);
			free(cur);
			return;
		}
		prev = cur;
		cur = cur->next;
	}
	pri_error("Can't destroy call %d!\n", cr);
}

static void q931_destroycall(struct pri *pri, int cr)
{
	return q931_destroy(pri, cr, NULL);
}


void __q931_destroycall(struct pri *pri, q931_call *c) 
{
	if (pri && c)
		q931_destroy(pri,0, c);
	return;
}

static int add_ie(struct pri *pri, q931_call *call, int msgtype, int ie, q931_ie *iet, int maxlen, int *codeset)
{
	unsigned int x;
	int res;
	int have_shift;
	for (x=0;x<sizeof(ies) / sizeof(ies[0]);x++) {
		if (ies[x].ie == ie) {
			/* This is our baby */
			if (ies[x].transmit) {
				/* Prepend with CODE SHIFT IE if required */
				if (*codeset != Q931_IE_CODESET(ies[x].ie)) {
					/* Locking shift to codeset 0 isn't possible */
					iet->ie = Q931_IE_CODESET(ies[x].ie) | (Q931_IE_CODESET(ies[x].ie) ? Q931_LOCKING_SHIFT : Q931_NON_LOCKING_SHIFT);
					have_shift = 1;
					iet = (q931_ie *)((char *)iet + 1);
					maxlen--;
				}
				else
					have_shift = 0;
				iet->ie = ie;
				res = ies[x].transmit(ie, pri, call, msgtype, iet, maxlen);
				/* Error if res < 0 or ignored if res == 0 */
				if (res <= 0)
					return res;
				if ((iet->ie & 0x80) == 0) /* Multibyte IE */
					iet->len = res - 2;
				if (have_shift) {
					if (Q931_IE_CODESET(ies[x].ie))
						*codeset = Q931_IE_CODESET(ies[x].ie);
					return res + 1; /* Shift is single-byte IE */
				}
				return res;
			} else {
				pri_error("!! Don't know how to add an IE %s (%d)\n", ie2str(ie), ie);
				return -1;
			}
		}
	}
	pri_error("!! Unknown IE %d (%s)\n", ie, ie2str(ie));
	return -1;
}

static char *disc2str(int disc)
{
	static struct msgtype discs[] = {
		{ Q931_PROTOCOL_DISCRIMINATOR, "Q.931" },
		{ GR303_PROTOCOL_DISCRIMINATOR, "GR-303" },
		{ 0x3, "AT&T Maintenance" },
		{ 0x43, "New AT&T Maintenance" },
	};
	return code2str(disc, discs, sizeof(discs) / sizeof(discs[0]));
}

void q931_dump(q931_h *h, int len, int txrx)
{
	q931_mh *mh;
	char c;
	int x=0, r;
	int cur_codeset;
	int codeset;
	c = txrx ? '>' : '<';
	pri_message("%c Protocol Discriminator: %s (%d)  len=%d\n", c, disc2str(h->pd), h->pd, len);
	pri_message("%c Call Ref: len=%2d (reference %d/0x%X) (%s)\n", c, h->crlen, q931_cr(h), q931_cr(h), (h->crv[0] & 0x80) ? "Terminator" : "Originator");
	/* Message header begins at the end of the call reference number */
	mh = (q931_mh *)(h->contents + h->crlen);
	pri_message("%c Message type: %s (%d)\n", c, msg2str(mh->msg), mh->msg);
	/* Drop length of header, including call reference */
	len -= (h->crlen + 3);
	codeset = cur_codeset = 0;
	while(x < len) {
		r = ielen((q931_ie *)(mh->data + x));
		q931_dumpie(cur_codeset, (q931_ie *)(mh->data + x), c);
		switch (mh->data[x] & 0xf8) {
		case Q931_LOCKING_SHIFT:
			if ((mh->data[x] & 7) > 0)
				codeset = cur_codeset = mh->data[x] & 7;
			break;
		case Q931_NON_LOCKING_SHIFT:
			cur_codeset = mh->data[x] & 7;
			break;
		default:
			/* Reset temporary codeset change */
			cur_codeset = codeset;
		}
		x += r;
	}
	if (x > len) 
		pri_error("XXX Message longer than it should be?? XXX\n");
}

static int q931_handle_ie(int codeset, struct pri *pri, q931_call *c, int msg, q931_ie *ie)
{
	unsigned int x;
	int full_ie = Q931_FULL_IE(codeset, ie->ie);
	if (pri->debug & PRI_DEBUG_Q931_STATE)
		pri_message("-- Processing IE %d (cs%d, %s)\n", ie->ie, codeset, ie2str(full_ie));
	for (x=0;x<sizeof(ies) / sizeof(ies[0]);x++) {
		if (full_ie == ies[x].ie) {
			if (ies[x].receive)
				return ies[x].receive(full_ie, pri, c, msg, ie, ielen(ie));
			else {
				if (pri->debug & PRI_DEBUG_Q931_ANOMALY)
					pri_error("!! No handler for IE %d (cs%d, %s)\n", ie->ie, codeset, ie2str(full_ie));
				return -1;
			}
		}
	}
	pri_message("!! Unknown IE %d (cs%d, %s)\n", ie->ie, codeset, ie2str(full_ie));
	return -1;
}

static void init_header(struct pri *pri, q931_call *call, char *buf, q931_h **hb, q931_mh **mhb, int *len)
{
	/* Returns header and message header and modifies length in place */
	q931_h *h = (q931_h *)buf;
	q931_mh * mh = (q931_mh *)(h->contents + 2);
	h->pd = pri->protodisc;
	h->x0 = 0;		/* Reserved 0 */
	h->crlen = 2;	/* Two bytes of Call Reference.  Invert the top bit to make it from our sense */
	if (call->cr || call->forceinvert) {
		h->crv[0] = ((call->cr ^ 0x8000) & 0xff00) >> 8;
		h->crv[1] = (call->cr & 0xff);
	} else {
		/* Unless of course this has no call reference */
		h->crv[0] = 0;
		h->crv[1] = 0;
	}
	if (pri->subchannel) {
		/* On GR-303, top bit is always 0 */
		h->crv[0] &= 0x7f;
	}
	mh->f = 0;
	*hb = h;
	*mhb = mh;
	*len -= 5;
	
}

static int q931_xmit(struct pri *pri, q931_h *h, int len, int cr)
{
	q921_transmit_iframe(pri, h, len, cr);
	/* The transmit operation might dump the q921 header, so logging the q931
	   message body after the transmit puts the sections of the message in the
	   right order in the log */
	if (pri->debug & PRI_DEBUG_Q931_DUMP)
		q931_dump(h, len, 1);
#ifdef LIBPRI_COUNTERS
	pri->q931_txcount++;
#endif
	return 0;
}

static int send_message(struct pri *pri, q931_call *c, int msgtype, int ies[])
{
	unsigned char buf[1024];
	q931_h *h;
	q931_mh *mh;
	int len;
	int res;
	int offset=0;
	int x;
	int codeset;
	memset(buf, 0, sizeof(buf));
	len = sizeof(buf);
	init_header(pri, c, buf, &h, &mh, &len);
	mh->msg = msgtype;
	x=0;
	codeset = 0;
	while(ies[x] > -1) {
		res = add_ie(pri, c, mh->msg, ies[x], (q931_ie *)(mh->data + offset), len, &codeset);
		if (res < 0) {
			pri_error("!! Unable to add IE '%s'\n", ie2str(ies[x]));
			return -1;
		}
		offset += res;
		len -= res;
		x++;
	}
	/* Invert the logic */
	len = sizeof(buf) - len;
	q931_xmit(pri, h, len, 1);
	c->acked = 1;
	return 0;
}

static int status_ies[] = { Q931_CAUSE, Q931_CALL_STATE, -1 };

static int q931_status(struct pri *pri, q931_call *c, int cause)
{
	q931_call *cur = NULL;
	if (!cause)
		cause = PRI_CAUSE_RESPONSE_TO_STATUS_ENQUIRY;
	if (c->cr > -1)
		cur = *pri->callpool;
	while(cur) {
		if (cur->cr == c->cr) {
			cur->cause=cause;
			cur->causecode = CODE_CCITT;
			cur->causeloc = LOC_USER;
			break;
		}
		cur = cur->next;
	}
	if (!cur) {
		pri_message("YYY Here we get reset YYY\n");
		/* something went wrong, respond with "no such call" */
		c->ourcallstate = Q931_CALL_STATE_NULL;
		c->peercallstate = Q931_CALL_STATE_NULL;
		cur=c;
	}
	return send_message(pri, cur, Q931_STATUS, status_ies);
}

static int information_ies[] = { Q931_CALLED_PARTY_NUMBER, -1 };

int q931_information(struct pri *pri, q931_call *c, char digit)
{
	c->callednum[0]=digit;
	c->callednum[1]='\0';
	return send_message(pri, c, Q931_INFORMATION, information_ies);
}

static int restart_ack_ies[] = { Q931_CHANNEL_IDENT, Q931_RESTART_INDICATOR, -1 };

static int restart_ack(struct pri *pri, q931_call *c)
{
	c->ourcallstate = Q931_CALL_STATE_NULL;
	c->peercallstate = Q931_CALL_STATE_NULL;
	return send_message(pri, c, Q931_RESTART_ACKNOWLEDGE, restart_ack_ies);
}

static int notify_ies[] = { Q931_IE_NOTIFY_IND, -1 };

int q931_notify(struct pri *pri, q931_call *c, int channel, int info)
{
	if (info >= 0)
		c->notify = info & 0x7F;
	else
		c->notify = -1;
	return send_message(pri, c, Q931_NOTIFY, notify_ies);
}

#ifdef ALERTING_NO_PROGRESS
static int call_progress_ies[] = { -1 };
#else
static int call_progress_ies[] = { Q931_PROGRESS_INDICATOR, -1 };
#endif

int q931_call_progress(struct pri *pri, q931_call *c, int channel, int info)
{
	if (channel) { 
		c->ds1no = (channel & 0xff00) >> 8;
		channel &= 0xff;
		c->channelno = channel;		
	}
	if (info) {
		c->progloc = LOC_PRIV_NET_LOCAL_USER;
		c->progcode = CODE_CCITT;
		c->progress = Q931_PROG_INBAND_AVAILABLE;
	} else
		c->progress = -1;
	c->alive = 1;
	return send_message(pri, c, Q931_PROGRESS, call_progress_ies);
}

#ifdef ALERTING_NO_PROGRESS
static int call_proceeding_ies[] = { Q931_CHANNEL_IDENT, -1 };
#else
static int call_proceeding_ies[] = { Q931_CHANNEL_IDENT, Q931_PROGRESS_INDICATOR, -1 };
#endif

int q931_call_proceeding(struct pri *pri, q931_call *c, int channel, int info)
{
	if (channel) { 
		c->ds1no = (channel & 0xff00) >> 8;
		channel &= 0xff;
		c->channelno = channel;		
	}
	c->chanflags &= ~FLAG_PREFERRED;
	c->chanflags |= FLAG_EXCLUSIVE;
	c->ourcallstate = Q931_CALL_STATE_INCOMING_CALL_PROCEEDING;
	c->peercallstate = Q931_CALL_STATE_OUTGOING_CALL_PROCEEDING;
	if (info) {
		c->progloc = LOC_PRIV_NET_LOCAL_USER;
		c->progcode = CODE_CCITT;
		c->progress = Q931_PROG_INBAND_AVAILABLE;
	} else
		c->progress = -1;
	c->proc = 1;
	c->alive = 1;
	return send_message(pri, c, Q931_CALL_PROCEEDING, call_proceeding_ies);
}
#ifndef ALERTING_NO_PROGRESS
static int alerting_ies[] = { Q931_PROGRESS_INDICATOR, -1 };
#else
static int alerting_ies[] = { -1 };
#endif

int q931_alerting(struct pri *pri, q931_call *c, int channel, int info)
{
	if (!c->proc) 
		q931_call_proceeding(pri, c, channel, 0);
	if (info) {
		c->progloc = LOC_PRIV_NET_LOCAL_USER;
		c->progcode = CODE_CCITT;
		c->progress = Q931_PROG_INBAND_AVAILABLE;
	} else
		c->progress = -1;
	c->ourcallstate = Q931_CALL_STATE_CALL_RECEIVED;
	c->peercallstate = Q931_CALL_STATE_CALL_DELIVERED;
	c->alive = 1;
	return send_message(pri, c, Q931_ALERTING, alerting_ies);
}

static int connect_ies[] = {  Q931_CHANNEL_IDENT, Q931_PROGRESS_INDICATOR, -1 };
 
int q931_setup_ack(struct pri *pri, q931_call *c, int channel, int nonisdn)
{
	if (channel) { 
		c->ds1no = (channel & 0xff00) >> 8;
		channel &= 0xff;
		c->channelno = channel;		
	}
	c->chanflags &= ~FLAG_PREFERRED;
	c->chanflags |= FLAG_EXCLUSIVE;
	if (nonisdn && (pri->switchtype != PRI_SWITCH_DMS100)) {
		c->progloc  = LOC_PRIV_NET_LOCAL_USER;
		c->progcode = CODE_CCITT;
		c->progress = Q931_PROG_CALLED_NOT_ISDN;
	} else
		c->progress = -1;
	c->ourcallstate = Q931_CALL_STATE_OVERLAP_RECEIVING;
	c->peercallstate = Q931_CALL_STATE_OVERLAP_SENDING;
	c->alive = 1;
	return send_message(pri, c, Q931_SETUP_ACKNOWLEDGE, connect_ies);
}

static void pri_connect_timeout(void *data)
{
	struct q931_call *c = data;
	struct pri *pri = c->pri;
	if (pri->debug & PRI_DEBUG_Q931_STATE)
		pri_message("Timed out looking for connect acknowledge\n");
	q931_disconnect(pri, c, PRI_CAUSE_NORMAL_CLEARING);
	
}

static void pri_release_timeout(void *data)
{
	struct q931_call *c = data;
	struct pri *pri = c->pri;
	if (pri->debug & PRI_DEBUG_Q931_STATE)
		pri_message("Timed out looking for release complete\n");
	c->t308_timedout++;
	c->alive = 1;
	q931_release(pri, c, PRI_CAUSE_NORMAL_CLEARING);
}

static void pri_release_finaltimeout(void *data)
{
	struct q931_call *c = data;
	struct pri *pri = c->pri;
	c->alive = 1;
	if (pri->debug & PRI_DEBUG_Q931_STATE)
		pri_message("Final time-out looking for release complete\n");
	c->t308_timedout++;
	c->ourcallstate = Q931_CALL_STATE_NULL;
	c->peercallstate = Q931_CALL_STATE_NULL;
	pri->schedev = 1;
	pri->ev.e = PRI_EVENT_HANGUP_ACK;
	pri->ev.hangup.channel = c->channelno;
	pri->ev.hangup.cref = c->cr;
	pri->ev.hangup.cause = c->cause;
	pri->ev.hangup.call = c;
	q931_hangup(pri, c, c->cause);
}

static void pri_disconnect_timeout(void *data)
{
	struct q931_call *c = data;
	struct pri *pri = c->pri;
	if (pri->debug & PRI_DEBUG_Q931_STATE)
		p