q921.c

Q.931/Q.921 source code compiles

					lastframe->h.p_f = 1;
					/* Update nr */
					lastframe->h.n_r = pri->v_r;
					pri->v_na = pri->v_r;
					q921_transmit(pri, (q921_h *)&lastframe->h, lastframe->len);
				}
			}
			if (pri->debug & PRI_DEBUG_Q921_DUMP)
			      pri_message(pri, "-- Rescheduling retransmission (%d)\n", pri->retrans);
			pri->t200_timer = pri_schedule_event(pri, pri->timers[PRI_TIMER_T200], t200_expire, pri);
		} else {
			if (pri->debug & PRI_DEBUG_Q921_STATE)
			      pri_message(pri, "-- Timeout occured, restarting PRI\n");
			if (pri->debug & PRI_DEBUG_Q921_STATE && pri->q921_state != Q921_LINK_CONNECTION_RELEASED)
			     pri_message(pri, DBGHEAD "q921_state now is Q921_LINK_CONNECTION_RELEASED\n",DBGINFO);
			pri->q921_state = Q921_LINK_CONNECTION_RELEASED;
			     pri->t200_timer = 0;
			if (pri->bri && pri->master) {
				q921_tei_release_and_reacquire(pri->master);
				return;
			} else {
				q921_dchannel_down(pri);
				q921_start(pri, 1);
				pri->schedev = 1;
			}
		}
	} else if (pri->solicitfbit) {
		if (pri->debug & PRI_DEBUG_Q921_DUMP)
			pri_message(pri, "-- Retrying poll with f-bit\n");
		if (pri->retrans < pri->timers[PRI_TIMER_N200]) {
			pri->retrans++;
			pri->solicitfbit = 1;
			q921_rr(pri, 1, 1);
			pri->t200_timer = pri_schedule_event(pri, pri->timers[PRI_TIMER_T200], t200_expire, pri);
		} else {
			if (pri->debug & PRI_DEBUG_Q921_STATE)
				pri_message(pri, "-- Timeout occured, restarting PRI\n");
			if (pri->debug & PRI_DEBUG_Q921_STATE && pri->q921_state != Q921_LINK_CONNECTION_RELEASED)
				pri_message(pri, DBGHEAD "q921_state now is Q921_LINK_CONNECTION_RELEASED\n", DBGINFO);
			pri->q921_state = Q921_LINK_CONNECTION_RELEASED;
			pri->t200_timer = 0;
			if (pri->bri && pri->master) {
				q921_tei_release_and_reacquire(pri->master);
				return;
			} else {
				q921_dchannel_down(pri);
				q921_start(pri, 1);
				pri->schedev = 1;
			}
		}
	} else {
		pri_error(pri, "T200 counter expired, nothing to send...\n");
	   	pri->t200_timer = 0;
	}
}

int q921_transmit_iframe(struct pri *pri, void *buf, int len, int cr)
{
	q921_frame *f, *prev=NULL;

	for (f=pri->txqueue; f; f = f->next) prev = f;
	f = calloc(1, sizeof(q921_frame) + len + 2);
	if (f) {
		Q921_INIT(pri, f->h);
		switch(pri->localtype) {
		case PRI_NETWORK:
			if (cr)
				f->h.h.c_r = 1;
			else
				f->h.h.c_r = 0;
		break;
		case PRI_CPE:
			if (cr)
				f->h.h.c_r = 0;
			else
				f->h.h.c_r = 1;
		break;
		}
		f->next = NULL;
		f->transmitted = 0;
		f->len = len + 4;
		memcpy(f->h.data, buf, len);
		f->h.n_s = pri->v_s;
		f->h.n_r = pri->v_r;
		pri->v_s++;
		pri->v_na = pri->v_r;
		f->h.p_f = 0;
		f->h.ft = 0;
		if (prev)
			prev->next = f;
		else
			pri->txqueue = f;
		/* Immediately transmit unless we're in a recovery state, or the window
		   size is too big */
		if (!pri->retrans && !pri->busy) {
			if (pri->windowlen < pri->window) {
				pri->windowlen++;
				q921_transmit(pri, (q921_h *)(&f->h), f->len);
				f->transmitted++;
			} else {
				if (pri->debug & PRI_DEBUG_Q921_DUMP)
					pri_message(pri, "Delaying transmission of %d, window is %d/%d long\n", 
						f->h.n_s, pri->windowlen, pri->window);
			}
		}
		if (pri->t203_timer) {
			if (pri->debug & PRI_DEBUG_Q921_DUMP)
				pri_message(pri, "Stopping T_203 timer\n");
			pri_schedule_del(pri, pri->t203_timer);
			pri->t203_timer = 0;
		}
		if (pri->debug & PRI_DEBUG_Q921_DUMP)
			pri_message(pri, "Starting T_200 timer\n");
		reschedule_t200(pri);		
	} else {
		pri_error(pri, "!! Out of memory for Q.921 transmit\n");
		return -1;
	}
	return 0;
}

static void t203_expire(void *vpri)
{
	struct pri *pri = vpri;
	if (pri->q921_state == Q921_LINK_CONNECTION_ESTABLISHED) {
		if (pri->debug & PRI_DEBUG_Q921_DUMP)
			pri_message(pri, "T203 counter expired, sending RR and scheduling T203 again\n");
		/* Solicit an F-bit in the other's RR */
		pri->solicitfbit = 1;
		pri->retrans = 0;
		q921_rr(pri, 1, 1);
		/* Start timer T200 to resend our RR if we don't get it */
		pri->t203_timer = pri_schedule_event(pri, pri->timers[PRI_TIMER_T200], t200_expire, pri);
	} else {
		if (pri->debug & PRI_DEBUG_Q921_DUMP)
			pri_message(pri, "T203 counter expired in weird state %d\n", pri->q921_state);
		pri->t203_timer = 0;
	}
}
static pri_event *q921_handle_iframe(struct pri *pri, q921_i *i, int len)
{
	int res;
	pri_event *ev;

	pri->solicitfbit = 0;
	/* Make sure this is a valid packet */
	if (i->n_s == pri->v_r) {
		/* Increment next expected I-frame */
		Q921_INC(pri->v_r);
		/* Handle their ACK */
		pri->sentrej = 0;
		ev = q921_ack_rx(pri, i->n_r, 0);
		if (ev)
			return ev;
		if (i->p_f) {
			/* If the Poll/Final bit is set, immediate send the RR */
			q921_rr(pri, 1, 0);
		} else if (pri->busy || pri->retrans) {
			q921_rr(pri, 0, 0); 
		}
		/* Receive Q.931 data */
		res = q931_receive(pri, (q931_h *)i->data, len - 4);
		/* Send an RR if one wasn't sent already */
		if (pri->v_na != pri->v_r) 
			q921_rr(pri, 0, 0);
		if (res == -1) {
			return NULL;
		}
		if (res & Q931_RES_HAVEEVENT)
			return &pri->ev;
	} else {
		/* If we haven't already sent a reject, send it now, otherwise
		   we are obliged to RR */
		if (!pri->sentrej)
			q921_reject(pri, i->p_f);
		else if (i->p_f)
			q921_rr(pri, 1, 0);
	}
	return NULL;
}

void q921_dump(struct pri *pri, q921_h *h, int len, int showraw, int txrx)
{
	int x;
        char *type;
	char direction_tag;
	
	direction_tag = txrx ? '>' : '<';
	if (showraw) {
		char *buf = malloc(len * 3 + 1);
		int buflen = 0;
		if (buf) {
			for (x=0;x<len;x++) 
				buflen += sprintf(buf + buflen, "%02x ", h->raw[x]);
			pri_message(pri, "\n%c [ %s]\n", direction_tag, buf);
			free(buf);
		}
	}

	switch (h->h.data[0] & Q921_FRAMETYPE_MASK) {
	case 0:
	case 2:
		pri_message(pri, "\n%c Informational frame:\n", direction_tag);
		break;
	case 1:
		pri_message(pri, "\n%c Supervisory frame:\n", direction_tag);
		break;
	case 3:
		pri_message(pri, "\n%c Unnumbered frame:\n", direction_tag);
		break;
	}
	
	pri_message(pri, 
"%c SAPI: %02d  C/R: %d EA: %d\n"
"%c  TEI: %03d        EA: %d\n", 
    	direction_tag,
	h->h.sapi, 
	h->h.c_r,
	h->h.ea1,
    	direction_tag,
	h->h.tei,
	h->h.ea2);

	switch (h->h.data[0] & Q921_FRAMETYPE_MASK) {
	case 0:
	case 2:
		/* Informational frame */
		pri_message(pri, 
"%c N(S): %03d   0: %d\n"
"%c N(R): %03d   P: %d\n"
"%c %d bytes of data\n",
    	direction_tag,
	h->i.n_s,
	h->i.ft,
    	direction_tag,
	h->i.n_r,
	h->i.p_f, 
    	direction_tag,
	len - 4);
		break;
	case 1:
		/* Supervisory frame */
		type = "???";
		switch (h->s.ss) {
		case 0:
			type = "RR (receive ready)";
			break;
		case 1:
			type = "RNR (receive not ready)";
			break;
		case 2:
			type = "REJ (reject)";
			break;
		}
		pri_message(pri, 
"%c Zero: %d     S: %d 01: %d  [ %s ]\n"
"%c N(R): %03d P/F: %d\n"
"%c %d bytes of data\n",
    	direction_tag,
	h->s.x0,
	h->s.ss,
	h->s.ft,
	type,
	direction_tag,
	h->s.n_r,
	h->s.p_f, 
	direction_tag,
	len - 4);
		break;
	case 3:		
		/* Unnumbered frame */
		type = "???";
		if (h->u.ft == 3) {
			switch (h->u.m3) {
			case 0:
				if (h->u.m2 == 3)
					type = "DM (disconnect mode)";
				else if (h->u.m2 == 0)
					type = "UI (unnumbered information)";
				break;
			case 2:
				if (h->u.m2 == 0)
					type = "DISC (disconnect)";
				break;
			case 3:
			       	if (h->u.m2 == 3)
					type = "SABME (set asynchronous balanced mode extended)";
				else if (h->u.m2 == 0)
					type = "UA (unnumbered acknowledgement)";
				break;
			case 4:
				if (h->u.m2 == 1)
					type = "FRMR (frame reject)";
				break;
			case 5:
				if (h->u.m2 == 3)
					type = "XID (exchange identification note)";
				break;
			}
		}
		pri_message(pri, 
"%c   M3: %d   P/F: %d M2: %d 11: %d  [ %s ]\n"
"%c %d bytes of data\n",
	direction_tag,
	h->u.m3,
	h->u.p_f,
	h->u.m2,
	h->u.ft,
	type,
	direction_tag,
	len - 3);
		break;
	};

	if ((h->u.ft == 3) && (h->u.m3 == 0) && (h->u.m2 == 0) && (h->u.data[0] == 0x0f)) {
		int ri;
		int tei;

		ri = (h->u.data[1] << 8) | h->u.data[2];
		tei = (h->u.data[4] >> 1);
		/* TEI assignment related */
		switch (h->u.data[3]) {
		case Q921_TEI_IDENTITY_REQUEST:
			type = "TEI Identity Request";
			break;
		case Q921_TEI_IDENTITY_ASSIGNED:
			type = "TEI Identity Assigned";
			break;
		case Q921_TEI_IDENTITY_CHECK_REQUEST:
			type = "TEI Identity Check Request";
			break;
		case Q921_TEI_IDENTITY_REMOVE:
			type = "TEI Identity Remove";
			break;
		case Q921_TEI_IDENTITY_DENIED:
			type = "TEI Identity Denied";
			break;
		case Q921_TEI_IDENTITY_CHECK_RESPONSE:
			type = "TEI Identity Check Response";
			break;
		case Q921_TEI_IDENTITY_VERIFY:
			type = "TEI Identity Verify";
			break;
		default:
			type = "Unknown";
			break;
		}
		pri_message(pri, "%c MDL Message: %s (%d)\n", direction_tag, type, h->u.data[3]);
		pri_message(pri, "%c RI: %d\n", direction_tag, ri);
		pri_message(pri, "%c Ai: %d E:%d\n", direction_tag, (h->u.data[4] >> 1) & 0x7f, h->u.data[4] & 1);
	}
}

static pri_event *q921_dchannel_up(struct pri *pri)
{
	/* Reset counters, etc */
	q921_reset(pri);
	
	/* Stop any SABME retransmissions */
	if (pri->sabme_timer) {
		pri_schedule_del(pri, pri->sabme_timer);
		pri->sabme_timer = 0;
	}
	
	/* Reset any rejects */
	pri->sentrej = 0;
	
	/* Go into connection established state */
	if (pri->debug & PRI_DEBUG_Q921_STATE && pri->q921_state != Q921_LINK_CONNECTION_ESTABLISHED)
		pri_message(pri, DBGHEAD "q921_state now is Q921_LINK_CONNECTION_ESTABLISHED\n", DBGINFO);
	pri->q921_state = Q921_LINK_CONNECTION_ESTABLISHED;

	/* Start the T203 timer */
	pri->t203_timer = pri_schedule_event(pri, pri->timers[PRI_TIMER_T203], t203_expire, pri);
	
	/* Notify Layer 3 */
	q931_dl_indication(pri, PRI_EVENT_DCHAN_UP);

	/* Report event that D-Channel is now up */
	pri->ev.gen.e = PRI_EVENT_DCHAN_UP;
	return &pri->ev;
}

static pri_event *q921_dchannel_down(struct pri *pri)
{
	/* Reset counters, reset sabme timer etc */
	q921_reset(pri);
	
	/* Notify Layer 3 */
	q931_dl_indication(pri, PRI_EVENT_DCHAN_DOWN);

	/* Report event that D-Channel is now up */
	pri->ev.gen.e = PRI_EVENT_DCHAN_DOWN;
	return &pri->ev;
}

void q921_reset(struct pri *pri)
{
	/* Having gotten a SABME we MUST reset our entire state */
	pri->v_s = 0;
	pri->v_a = 0;
	pri->v_r = 0;
	pri->v_na = 0;
	pri->window = pri->timers[PRI_TIMER_K];
	pri->windowlen = 0;
	if (pri->sabme_timer)
		pri_schedule_del(pri, pri->sabme_timer);
	if (pri->t203_timer)
		pri_schedule_del(pri, pri->t203_timer);
	if (pri->t200_timer)
		pri_schedule_del(pri, pri->t200_timer);
	pri->sabme_timer = 0;
	pri->sabme_count = 0;
	pri->t203_timer = 0;
	pri->t200_timer = 0;
	pri->busy = 0;
	pri->solicitfbit = 0;
	if (pri->debug & PRI_DEBUG_Q921_STATE && pri->q921_state != Q921_LINK_CONNECTION_RELEASED)
		pri_message(pri, DBGHEAD "q921_state now is Q921_LINK_CONNECTION_RELEASED\n", DBGINFO);
	pri->q921_state = Q921_LINK_CONNECTION_RELEASED;
	pri->retrans = 0;
	pri->sentrej = 0;