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ISDN BRI does not recover from line faults

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Q.921 was getting stuck in state 2 (Q921_ASSIGN_AWAITING_TEI).  For some
reason the network was removing the TEI.  Libpri then immediately tried to
get a new TEI assigned.  The network did not reply to the N202(3) attempts
to get a new TEI.  Libpri then just gave up trying but did not leave the
state.  Some paths in Q.921 Figure B.3 were not implemented.

Q.921 now transitions to the Q921_TEI_UNASSIGNED state when the N202 count
is exceeded.  Q.921 will wait there until an incoming or outgoing call is
attempted.

* Fixed initializing the n202_counter.  Not initializing the n202_counter
would cause the Q921_TEI_IDENTITY_REQUEST to unexpectedly not go out and
due to how state transitions were done, Q.921 would get stuck in the
Q921_ASSIGN_AWAITING_TEI state.

* Fixed start T202 timer fail causing Q.921 to get stuck in the
Q921_ASSIGN_AWAITING_TEI state if the network did not respond to the
request.

* Fixed handling of Q921_TEI_IDENTITY_REMOVE to do the MDL-REMOVE
primitive (q921_mdl_remove()) instead of transitioning directly to the
Q921_TEI_UNASSIGNED state.  Necessary state clean-up was not getting done.

* Minor tweaks to q921_mdl_remove().  The worst problem was erroneously
generating an error message.

* Fixed potential for sending I-frames with an invalid TEI.  The I-frame
could have been queued when Q.921 did not have an assigned TEI.

* Fixed testing of the q931_receive() return value when a UI-frame is
received.

(closes issue #17570)
Reported by: jcovert
Patches:
      issue17570_v1.4.11.3_v3.patch uploaded by rmudgett (license 664)
      issue17570_v1.4_v3.patch uploaded by rmudgett (license 664)
Tested by: jcovert, rmudgett


git-svn-id: https://origsvn.digium.com/svn/libpri/branches/1.4@1918 2fbb986a-6c06-0410-b554-c9c1f0a7f128
This commit is contained in:
Richard Mudgett 2010-08-30 17:53:33 +00:00
parent e12b0913ec
commit da0b057536
1 changed files with 87 additions and 30 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

117
q921.c
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@ -196,19 +196,49 @@ static void q921_send_tei(struct pri *ctrl, int message, int ri, int ai, int isc
free(f);
}
static void q921_tei_request(void *vpri)
static void t202_expire(void *vpri)
{
struct pri *ctrl = (struct pri *)vpri;
ctrl->n202_counter++;
if (ctrl->n202_counter > ctrl->timers[PRI_TIMER_N202]) {
pri_error(ctrl, "Unable to receive TEI from network!\n");
ctrl->n202_counter = 0;
/* Start the TEI request timer. */
pri_schedule_del(ctrl, ctrl->t202_timer);
ctrl->t202_timer =
pri_schedule_event(ctrl, ctrl->timers[PRI_TIMER_T202], t202_expire, ctrl);
++ctrl->n202_counter;
if (!ctrl->t202_timer || ctrl->n202_counter > ctrl->timers[PRI_TIMER_N202]) {
if (!ctrl->t202_timer) {
pri_error(ctrl, "Could not start T202 timer.");
} else {
pri_schedule_del(ctrl, ctrl->t202_timer);
ctrl->t202_timer = 0;
}
pri_error(ctrl, "Unable to receive TEI from network in state %d(%s)!\n",
ctrl->q921_state, q921_state2str(ctrl->q921_state));
switch (ctrl->q921_state) {
case Q921_ASSIGN_AWAITING_TEI:
break;
case Q921_ESTABLISH_AWAITING_TEI:
q921_discard_iqueue(ctrl);
/* DL-RELEASE indication */
q931_dl_indication(ctrl, PRI_EVENT_DCHAN_DOWN);
break;
default:
break;
}
q921_setstate(ctrl, Q921_TEI_UNASSIGNED);
return;
}
/* Send TEI request */
ctrl->ri = random() % 65535;
q921_send_tei(PRI_MASTER(ctrl), Q921_TEI_IDENTITY_REQUEST, ctrl->ri, Q921_TEI_GROUP, 1);
pri_schedule_del(ctrl, ctrl->t202_timer);
ctrl->t202_timer = pri_schedule_event(ctrl, ctrl->timers[PRI_TIMER_T202], q921_tei_request, ctrl);
}
static void q921_tei_request(struct pri *ctrl)
{
ctrl->n202_counter = 0;
t202_expire(ctrl);
}
static void q921_send_ua(struct pri *ctrl, int pfbit)
@ -397,6 +427,14 @@ static int q921_send_queued_iframes(struct pri *ctrl)
if (ctrl->debug & PRI_DEBUG_Q921_DUMP)
pri_message(ctrl, "-- Finally transmitting %d, since window opened up (%d)\n", f->h.n_s, ctrl->timers[PRI_TIMER_K]);
f->transmitted++;
/*
* Send the frame out on the assigned TEI.
* Done now because the frame may have been queued before we
* had an assigned TEI.
*/
f->h.h.tei = ctrl->tei;
f->h.n_s = ctrl->v_s;
f->h.n_r = ctrl->v_r;
f->h.ft = 0;
@ -619,9 +657,16 @@ int q921_transmit_iframe(struct pri *vpri, int tei, void *buf, int len, int cr)
/* We don't care what the tei is, since we only support one sub and one TEI */
ctrl = PRI_MASTER(vpri)->subchannel;
if (ctrl->q921_state == Q921_TEI_UNASSIGNED) {
q921_tei_request(ctrl);
switch (ctrl->q921_state) {
case Q921_TEI_UNASSIGNED:
q921_setstate(ctrl, Q921_ESTABLISH_AWAITING_TEI);
q921_tei_request(ctrl);
break;
case Q921_ASSIGN_AWAITING_TEI:
q921_setstate(ctrl, Q921_ESTABLISH_AWAITING_TEI);
break;
default:
break;
}
} else {
/* Should just be PTP modes, which shouldn't have subs */
@ -636,9 +681,7 @@ int q921_transmit_iframe(struct pri *vpri, int tei, void *buf, int len, int cr)
ctrl->l3initiated = 1;
q921_setstate(ctrl, Q921_AWAITING_ESTABLISHMENT);
/* For all rest, we've done the work to get us up prior to this and fall through */
case Q921_TEI_UNASSIGNED:
case Q921_ESTABLISH_AWAITING_TEI:
case Q921_ASSIGN_AWAITING_TEI:
case Q921_TIMER_RECOVERY:
case Q921_AWAITING_ESTABLISHMENT:
case Q921_MULTI_FRAME_ESTABLISHED:
@ -698,6 +741,8 @@ int q921_transmit_iframe(struct pri *vpri, int tei, void *buf, int len, int cr)
pri_error(ctrl, "!! Out of memory for Q.921 transmit\n");
return -1;
}
case Q921_TEI_UNASSIGNED:
case Q921_ASSIGN_AWAITING_TEI:
case Q921_AWAITING_RELEASE:
default:
pri_error(ctrl, "Cannot transmit frames in state %d(%s)\n",
@ -1049,6 +1094,8 @@ static pri_event *q921_receive_MDL(struct pri *ctrl, q921_u *h, int len)
q921_establish_data_link(ctrl);
ctrl->l3initiated = 1;
q921_setstate(ctrl, Q921_AWAITING_ESTABLISHMENT);
ctrl->ev.gen.e = PRI_EVENT_DCHAN_UP;
res = &ctrl->ev;
break;
default:
pri_error(ctrl, "Error 3\n");
@ -1072,10 +1119,17 @@ static pri_event *q921_receive_MDL(struct pri *ctrl, q921_u *h, int len)
if (!BRI_TE_PTMP(ctrl))
return NULL;
if (ctrl->subchannel->q921_state < Q921_TEI_ASSIGNED) {
/* We do not have a TEI. */
return NULL;
}
/* If it's addressed to the group TEI or to our TEI specifically, we respond */
if ((tei == Q921_TEI_GROUP) || (tei == ctrl->subchannel->tei)) {
q921_setstate(ctrl->subchannel, Q921_TEI_UNASSIGNED);
q921_mdl_remove(ctrl->subchannel);
q921_start(ctrl->subchannel);
}
break;
}
return res; /* Do we need to return something??? */
}
@ -1182,6 +1236,18 @@ static pri_event *q921_disc_rx(struct pri *ctrl, q921_h *h)
static void q921_mdl_remove(struct pri *ctrl)
{
int mdl_free_me;
if (BRI_NT_PTMP(ctrl)) {
if (ctrl == PRI_MASTER(ctrl)) {
pri_error(ctrl, "Bad bad bad! Cannot MDL-REMOVE master\n");
return;
}
mdl_free_me = 1;
} else {
mdl_free_me = 0;
}
switch (ctrl->q921_state) {
case Q921_TEI_ASSIGNED:
/* XXX: deviation! Since we don't have a UI queue, we just discard our I-queue */
@ -1192,7 +1258,6 @@ static void q921_mdl_remove(struct pri *ctrl)
q921_discard_iqueue(ctrl);
/* DL-RELEASE indication */
q931_dl_indication(ctrl, PRI_EVENT_DCHAN_DOWN);
stop_t200(ctrl);
q921_setstate(ctrl, Q921_TEI_UNASSIGNED);
break;
@ -1200,6 +1265,7 @@ static void q921_mdl_remove(struct pri *ctrl)
q921_discard_iqueue(ctrl);
/* DL-RELEASE confirm */
stop_t200(ctrl);
q921_setstate(ctrl, Q921_TEI_UNASSIGNED);
break;
case Q921_MULTI_FRAME_ESTABLISHED:
q921_discard_iqueue(ctrl);
@ -1215,19 +1281,14 @@ static void q921_mdl_remove(struct pri *ctrl)
q931_dl_indication(ctrl, PRI_EVENT_DCHAN_DOWN);
stop_t200(ctrl);
q921_setstate(ctrl, Q921_TEI_UNASSIGNED);
default:
pri_error(ctrl, "Cannot handle MDL remove when PRI is in state %d(%s)\n",
ctrl->q921_state, q921_state2str(ctrl->q921_state));
break;
default:
pri_error(ctrl, "MDL-REMOVE when in state %d(%s)\n",
ctrl->q921_state, q921_state2str(ctrl->q921_state));
return;
}
if (BRI_NT_PTMP(ctrl) && ctrl->q921_state == Q921_TEI_UNASSIGNED) {
if (ctrl == PRI_MASTER(ctrl)) {
pri_error(ctrl, "Bad bad bad! Asked to free master\n");
return;
}
ctrl->mdl_free_me = 1;
}
ctrl->mdl_free_me = mdl_free_me;
}
static int q921_mdl_handle_network_error(struct pri *ctrl, char error)
@ -2020,19 +2081,15 @@ static pri_event *__q921_receive_qualified(struct pri *ctrl, q921_h *h, int len)
break;
} else if (!h->u.m2) {
if ((ctrl->sapi == Q921_SAPI_LAYER2_MANAGEMENT) && (ctrl->tei == Q921_TEI_GROUP)) {
pri_error(ctrl, "I should never be called\n");
q921_receive_MDL(ctrl, (q921_u *)h, len);
ev = q921_receive_MDL(ctrl, (q921_u *)h, len);
} else {
int res;
res = q931_receive(ctrl, ctrl->tei, (q931_h *) h->u.data, len - 3);
if (res == -1) {
ev = NULL;
}
if (res & Q931_RES_HAVEEVENT)
if (res != -1 && (res & Q931_RES_HAVEEVENT)) {
ev = &ctrl->ev;
}
}
}
break;