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libpri/q921.c
Richard Mudgett 13beaacc80 libpri: Make TE-PTP mode respond to MDL TEI check requests. 
Some BRI devices in France insist on checking TEI's when in point-to-point
mode.  If they don't get a response for TEI 0 they drop layer 1 even
though libpri keeps trying to bring layer 2 up.

* Made q921_mdl_receive() handle TEI check request messages in TE-PTP
mode.  Had to change q921_mdl_send()/Q921_INIT() because the PTP modes do
not setup a link structure specifically for MDL as the PTMP modes do.

* Fixed q921_tei_check()/t201_expire() to check TEI's even if the network
side doesn't have any assigned.  This should make TE's that request the
TEI verify procedure (Q.921 Section 5.3.5) happy when the network side
doesn't have any TEI's allocated.

PRI-165
Reported by: Denis Alberto Martinez
Patches:
      jira_pri_165_ptp_respond_tei_check.patch (license #5621) patch uploaded by rmudgett
Review: https://reviewboard.asterisk.org/r/3434/



git-svn-id: https://origsvn.digium.com/svn/libpri/branches/1.4@2318 2fbb986a-6c06-0410-b554-c9c1f0a7f128
2014-04-18 17:44:31 +00:00

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/*
* libpri: An implementation of Primary Rate ISDN
*
* Written by Mark Spencer <markster@digium.com>
*
* Copyright (C) 2001-2005, Digium, Inc.
* All Rights Reserved.
*/
/*
* See http://www.asterisk.org for more information about
* the Asterisk project. Please do not directly contact
* any of the maintainers of this project for assistance;
* the project provides a web site, mailing lists and IRC
* channels for your use.
*
* This program is free software, distributed under the terms of
* the GNU General Public License Version 2 as published by the
* Free Software Foundation. See the LICENSE file included with
* this program for more details.
*
* In addition, when this program is distributed with Asterisk in
* any form that would qualify as a 'combined work' or as a
* 'derivative work' (but not mere aggregation), you can redistribute
* and/or modify the combination under the terms of the license
* provided with that copy of Asterisk, instead of the license
* terms granted here.
*/
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include "compat.h"
#include "libpri.h"
#include "pri_internal.h"
#include "pri_q921.h"
#include "pri_q931.h"
/*
* Define RANDOM_DROPS To randomly drop packets in order to simulate loss for testing
* retransmission functionality
*/
//#define RANDOM_DROPS 1
#define Q921_INIT(fr, l_sapi, l_tei) \
do { \
(fr)->h.sapi = l_sapi; \
(fr)->h.ea1 = 0; \
(fr)->h.ea2 = 1; \
(fr)->h.tei = l_tei; \
} while (0)
#define Q921_CLEAR_INIT(fr, l_sapi, l_tei) \
do { \
memset((fr), 0, sizeof(*(fr))); \
Q921_INIT((fr), (l_sapi), (l_tei)); \
} while (0)
static void q921_dump_pri(struct q921_link *link, char direction_tag);
static void q921_establish_data_link(struct q921_link *link);
static void q921_mdl_error(struct q921_link *link, char error);
static void q921_mdl_remove(struct q921_link *link);
static void q921_mdl_destroy(struct q921_link *link);
/*!
* \internal
* \brief Convert Q.921 TEI management message type to a string.
*
* \param message Q.921 TEI management message type to convert.
*
* \return TEI management message type name string
*/
static const char *q921_tei_mgmt2str(enum q921_tei_identity message)
{
switch (message) {
case Q921_TEI_IDENTITY_REQUEST:
return "TEI Identity Request";
case Q921_TEI_IDENTITY_ASSIGNED:
return "TEI Identity Assigned";
case Q921_TEI_IDENTITY_CHECK_REQUEST:
return "TEI Identity Check Request";
case Q921_TEI_IDENTITY_REMOVE:
return "TEI Identity Remove";
case Q921_TEI_IDENTITY_DENIED:
return "TEI Identity Denied";
case Q921_TEI_IDENTITY_CHECK_RESPONSE:
return "TEI Identity Check Response";
case Q921_TEI_IDENTITY_VERIFY:
return "TEI Identity Verify";
}
return "Unknown";
}
/*!
* \internal
* \brief Convert Q.921 state to a string.
*
* \param state Q.921 state to convert.
*
* \return State name string
*/
static const char *q921_state2str(enum q921_state state)
{
switch (state) {
case Q921_TEI_UNASSIGNED:
return "TEI unassigned";
case Q921_ASSIGN_AWAITING_TEI:
return "Assign awaiting TEI";
case Q921_ESTABLISH_AWAITING_TEI:
return "Establish awaiting TEI";
case Q921_TEI_ASSIGNED:
return "TEI assigned";
case Q921_AWAITING_ESTABLISHMENT:
return "Awaiting establishment";
case Q921_AWAITING_RELEASE:
return "Awaiting release";
case Q921_MULTI_FRAME_ESTABLISHED:
return "Multi-frame established";
case Q921_TIMER_RECOVERY:
return "Timer recovery";
}
return "Unknown state";
}
static void q921_setstate(struct q921_link *link, int newstate)
{
struct pri *ctrl;
ctrl = link->ctrl;
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
/*
* Suppress displaying these state transitions:
* Q921_MULTI_FRAME_ESTABLISHED <--> Q921_TIMER_RECOVERY
*
* Q921 keeps flipping back and forth between these two states
* when it has nothing better to do.
*/
switch (link->state) {
case Q921_MULTI_FRAME_ESTABLISHED:
case Q921_TIMER_RECOVERY:
switch (newstate) {
case Q921_MULTI_FRAME_ESTABLISHED:
case Q921_TIMER_RECOVERY:
/* Suppress displaying this state transition. */
link->state = newstate;
return;
default:
break;
}
break;
default:
break;
}
if (link->state != newstate) {
pri_message(ctrl, "Changing from state %d(%s) to %d(%s)\n",
link->state, q921_state2str(link->state),
newstate, q921_state2str(newstate));
}
}
link->state = newstate;
}
static void q921_discard_iqueue(struct q921_link *link)
{
struct q921_frame *f, *p;
f = link->tx_queue;
while (f) {
p = f;
f = f->next;
/* Free frame */
free(p);
}
link->tx_queue = NULL;
}
static int q921_transmit(struct pri *ctrl, q921_h *h, int len)
{
int res;
#ifdef RANDOM_DROPS
if (!(random() % 3)) {
pri_message(ctrl, " === Dropping Packet ===\n");
return 0;
}
#endif
ctrl->q921_txcount++;
/* Just send it raw */
if (ctrl->debug & (PRI_DEBUG_Q921_DUMP | PRI_DEBUG_Q921_RAW))
q921_dump(ctrl, h, len, ctrl->debug, 1);
/* Write an extra two bytes for the FCS */
res = ctrl->write_func ? ctrl->write_func(ctrl, h, len + 2) : 0;
if (res != (len + 2)) {
pri_error(ctrl, "Short write: %d/%d (%s)\n", res, len + 2, strerror(errno));
return -1;
}
return 0;
}
static void q921_mdl_send(struct pri *ctrl, enum q921_tei_identity message, int ri, int ai, int iscommand)
{
q921_u *f;
if (!(f = calloc(1, sizeof(*f) + 5)))
return;
Q921_INIT(f, Q921_SAPI_LAYER2_MANAGEMENT, Q921_TEI_GROUP);
f->h.c_r = (ctrl->localtype == PRI_NETWORK) ? iscommand : !iscommand;
f->ft = Q921_FRAMETYPE_U;
f->data[0] = 0x0f; /* Management entity */
f->data[1] = (ri >> 8) & 0xff;
f->data[2] = ri & 0xff;
f->data[3] = message;
f->data[4] = (ai << 1) | 1;
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl,
"Sending MDL message: %d(%s), TEI=%d\n",
message, q921_tei_mgmt2str(message), ai);
}
q921_transmit(ctrl, (q921_h *)f, 8);
free(f);
}
static void t202_expire(void *vlink)
{
struct q921_link *link = vlink;
struct pri *ctrl;
ctrl = link->ctrl;
/* Start the TEI request timer. */
pri_schedule_del(ctrl, link->t202_timer);
link->t202_timer =
pri_schedule_event(ctrl, ctrl->timers[PRI_TIMER_T202], t202_expire, link);
if (ctrl->l2_persistence != PRI_L2_PERSISTENCE_KEEP_UP) {
/* Only try to get a TEI for N202 times if layer 2 is not persistent. */
++link->n202_counter;
}
if (!link->t202_timer || link->n202_counter > ctrl->timers[PRI_TIMER_N202]) {
if (!link->t202_timer) {
pri_error(ctrl, "Could not start T202 timer.");
} else {
pri_schedule_del(ctrl, link->t202_timer);
link->t202_timer = 0;
}
pri_error(ctrl, "Unable to receive TEI from network in state %d(%s)!\n",
link->state, q921_state2str(link->state));
switch (link->state) {
case Q921_ASSIGN_AWAITING_TEI:
break;
case Q921_ESTABLISH_AWAITING_TEI:
q921_discard_iqueue(link);
/* DL-RELEASE indication */
q931_dl_event(link, Q931_DL_EVENT_DL_RELEASE_IND);
break;
default:
break;
}
q921_setstate(link, Q921_TEI_UNASSIGNED);
return;
}
/* Send TEI request */
link->ri = random() % 65535;
q921_mdl_send(ctrl, Q921_TEI_IDENTITY_REQUEST, link->ri, Q921_TEI_GROUP, 1);
}
static void q921_tei_request(struct q921_link *link)
{
link->n202_counter = 0;
t202_expire(link);
}
static void q921_tei_remove(struct pri *ctrl, int tei)
{
/*
* Q.921 Section 5.3.2 says we should send the remove message
* twice, in case of message loss.
*/
q921_mdl_send(ctrl, Q921_TEI_IDENTITY_REMOVE, 0, tei, 1);
q921_mdl_send(ctrl, Q921_TEI_IDENTITY_REMOVE, 0, tei, 1);
}
static void q921_send_dm(struct q921_link *link, int fbit)
{
q921_h h;
struct pri *ctrl;
ctrl = link->ctrl;
Q921_CLEAR_INIT(&h, link->sapi, link->tei);
h.u.m3 = 0; /* M3 = 0 */
h.u.m2 = 3; /* M2 = 3 */
h.u.p_f = fbit; /* Final set appropriately */
h.u.ft = Q921_FRAMETYPE_U;
switch (ctrl->localtype) {
case PRI_NETWORK:
h.h.c_r = 0;
break;
case PRI_CPE:
h.h.c_r = 1;
break;
default:
pri_error(ctrl, "Don't know how to DM on a type %d node\n", ctrl->localtype);
return;
}
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl, "TEI=%d Sending DM\n", link->tei);
}
q921_transmit(ctrl, &h, 4);
}
static void q921_send_disc(struct q921_link *link, int pbit)
{
q921_h h;
struct pri *ctrl;
ctrl = link->ctrl;
Q921_CLEAR_INIT(&h, link->sapi, link->tei);
h.u.m3 = 2; /* M3 = 2 */
h.u.m2 = 0; /* M2 = 0 */
h.u.p_f = pbit; /* Poll set appropriately */
h.u.ft = Q921_FRAMETYPE_U;
switch (ctrl->localtype) {
case PRI_NETWORK:
h.h.c_r = 0;
break;
case PRI_CPE:
h.h.c_r = 1;
break;
default:
pri_error(ctrl, "Don't know how to DISC on a type %d node\n", ctrl->localtype);
return;
}
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl, "TEI=%d Sending DISC\n", link->tei);
}
q921_transmit(ctrl, &h, 4);
}
static void q921_send_ua(struct q921_link *link, int fbit)
{
q921_h h;
struct pri *ctrl;
ctrl = link->ctrl;
Q921_CLEAR_INIT(&h, link->sapi, link->tei);
h.u.m3 = 3; /* M3 = 3 */
h.u.m2 = 0; /* M2 = 0 */
h.u.p_f = fbit; /* Final set appropriately */
h.u.ft = Q921_FRAMETYPE_U;
switch (ctrl->localtype) {
case PRI_NETWORK:
h.h.c_r = 0;
break;
case PRI_CPE:
h.h.c_r = 1;
break;
default:
pri_error(ctrl, "Don't know how to UA on a type %d node\n", ctrl->localtype);
return;
}
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl, "TEI=%d Sending UA\n", link->tei);
}
q921_transmit(ctrl, &h, 3);
}
static void q921_send_sabme(struct q921_link *link)
{
q921_h h;
struct pri *ctrl;
ctrl = link->ctrl;
Q921_CLEAR_INIT(&h, link->sapi, link->tei);
h.u.m3 = 3; /* M3 = 3 */
h.u.m2 = 3; /* M2 = 3 */
h.u.p_f = 1; /* Poll bit set */
h.u.ft = Q921_FRAMETYPE_U;
switch (ctrl->localtype) {
case PRI_NETWORK:
h.h.c_r = 1;
break;
case PRI_CPE:
h.h.c_r = 0;
break;
default:
pri_error(ctrl, "Don't know how to SABME on a type %d node\n", ctrl->localtype);
return;
}
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl, "TEI=%d Sending SABME\n", link->tei);
}
q921_transmit(ctrl, &h, 3);
}
static int q921_ack_packet(struct q921_link *link, int num)
{
struct q921_frame *f;
struct q921_frame *prev;
struct pri *ctrl;
ctrl = link->ctrl;
for (prev = NULL, f = link->tx_queue; f; prev = f, f = f->next) {
if (f->status != Q921_TX_FRAME_SENT) {
break;
}
if (f->h.n_s == num) {
/* Cancel each packet as necessary */
/* That's our packet */
if (prev)
prev->next = f->next;
else
link->tx_queue = f->next;
if (ctrl->debug & PRI_DEBUG_Q921_DUMP) {
pri_message(ctrl,
"-- ACKing N(S)=%d, tx_queue head is N(S)=%d (-1 is empty, -2 is not transmitted)\n",
f->h.n_s,
link->tx_queue
? link->tx_queue->status == Q921_TX_FRAME_SENT
? link->tx_queue->h.n_s
: -2
: -1);
}
/* Update v_a */
free(f);
return 1;
}
}
return 0;
}
static void t203_expire(void *vlink);
static void t200_expire(void *vlink);
#define restart_t200(link) reschedule_t200(link)
static void reschedule_t200(struct q921_link *link)
{
struct pri *ctrl;
ctrl = link->ctrl;
if (ctrl->debug & PRI_DEBUG_Q921_DUMP)
pri_message(ctrl, "-- Restarting T200 timer\n");
pri_schedule_del(ctrl, link->t200_timer);
link->t200_timer = pri_schedule_event(ctrl, ctrl->timers[PRI_TIMER_T200], t200_expire, link);
}
#if 0
static void reschedule_t203(struct q921_link *link)
{
struct pri *ctrl;
ctrl = link->ctrl;
if (ctrl->debug & PRI_DEBUG_Q921_DUMP)
pri_message(ctrl, "-- Restarting T203 timer\n");
pri_schedule_del(ctrl, link->t203_timer);
link->t203_timer = pri_schedule_event(ctrl, ctrl->timers[PRI_TIMER_T203], t203_expire, link);
}
#endif
static void start_t203(struct q921_link *link)
{
struct pri *ctrl;
ctrl = link->ctrl;
if (link->t203_timer) {
if (ctrl->debug & PRI_DEBUG_Q921_DUMP)
pri_message(ctrl, "T203 requested to start without stopping first\n");
pri_schedule_del(ctrl, link->t203_timer);
}
if (ctrl->debug & PRI_DEBUG_Q921_DUMP)
pri_message(ctrl, "-- Starting T203 timer\n");
link->t203_timer = pri_schedule_event(ctrl, ctrl->timers[PRI_TIMER_T203], t203_expire, link);
}
static void stop_t203(struct q921_link *link)
{
struct pri *ctrl;
ctrl = link->ctrl;
if (link->t203_timer) {
if (ctrl->debug & PRI_DEBUG_Q921_DUMP)
pri_message(ctrl, "-- Stopping T203 timer\n");
pri_schedule_del(ctrl, link->t203_timer);
link->t203_timer = 0;
} else {
if (ctrl->debug & PRI_DEBUG_Q921_DUMP)
pri_message(ctrl, "-- T203 requested to stop when not started\n");
}
}
static void start_t200(struct q921_link *link)
{
struct pri *ctrl;
ctrl = link->ctrl;
if (link->t200_timer) {
if (ctrl->debug & PRI_DEBUG_Q921_DUMP)
pri_message(ctrl, "T200 requested to start without stopping first\n");
pri_schedule_del(ctrl, link->t200_timer);
}
if (ctrl->debug & PRI_DEBUG_Q921_DUMP)
pri_message(ctrl, "-- Starting T200 timer\n");
link->t200_timer = pri_schedule_event(ctrl, ctrl->timers[PRI_TIMER_T200], t200_expire, link);
}
static void stop_t200(struct q921_link *link)
{
struct pri *ctrl;
ctrl = link->ctrl;
if (link->t200_timer) {
if (ctrl->debug & PRI_DEBUG_Q921_DUMP)
pri_message(ctrl, "-- Stopping T200 timer\n");
pri_schedule_del(ctrl, link->t200_timer);
link->t200_timer = 0;
} else {
if (ctrl->debug & PRI_DEBUG_Q921_DUMP)
pri_message(ctrl, "-- T200 requested to stop when not started\n");
}
}
/*!
* \internal
* \brief Initiate bringing up layer 2 link.
*
* \param link Layer 2 link to bring up.
*
* \return Nothing
*/
static void kick_start_link(struct q921_link *link)
{
struct pri *ctrl;
ctrl = link->ctrl;
switch (link->state) {
case Q921_TEI_UNASSIGNED:
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl, "Kick starting link from no TEI.\n");
}
q921_setstate(link, Q921_ESTABLISH_AWAITING_TEI);
q921_tei_request(link);
break;
case Q921_ASSIGN_AWAITING_TEI:
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl, "Kick starting link when awaiting TEI.\n");
}
q921_setstate(link, Q921_ESTABLISH_AWAITING_TEI);
break;
case Q921_TEI_ASSIGNED:
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl, "SAPI/TEI=%d/%d Kick starting link\n", link->sapi,
link->tei);
}
q921_discard_iqueue(link);
q921_establish_data_link(link);
link->l3_initiated = 1;
q921_setstate(link, Q921_AWAITING_ESTABLISHMENT);
break;
default:
break;
}
}
static void restart_timer_expire(void *vlink)
{
struct q921_link *link = vlink;
struct pri *ctrl;
ctrl = link->ctrl;
link->restart_timer = 0;
switch (link->state) {
case Q921_TEI_UNASSIGNED:
case Q921_ASSIGN_AWAITING_TEI:
case Q921_TEI_ASSIGNED:
/* Try to bring layer 2 up. */
kick_start_link(link);
break;
default:
/* Looks like someone forgot to stop the restart timer. */
pri_error(ctrl, "SAPI/TEI=%d/%d Link restart delay timer expired in state %d(%s)\n",
link->sapi, link->tei, link->state, q921_state2str(link->state));
break;
}
}
static void restart_timer_stop(struct q921_link *link)
{
struct pri *ctrl;
ctrl = link->ctrl;
pri_schedule_del(ctrl, link->restart_timer);
link->restart_timer = 0;
}
/*! \note Only call on the transition to state Q921_TEI_ASSIGNED or already there. */
static void restart_timer_start(struct q921_link *link)
{
struct pri *ctrl;
ctrl = link->ctrl;
if (ctrl->debug & PRI_DEBUG_Q921_DUMP) {
pri_message(ctrl, "SAPI/TEI=%d/%d Starting link restart delay timer\n",
link->sapi, link->tei);
}
pri_schedule_del(ctrl, link->restart_timer);
link->restart_timer =
pri_schedule_event(ctrl, ctrl->timers[PRI_TIMER_T200], restart_timer_expire, link);
}
/*! \note Only call on the transition to state Q921_TEI_ASSIGNED or already there. */
static pri_event *q921_check_delay_restart(struct q921_link *link)
{
pri_event *ev;
struct pri *ctrl;
ctrl = link->ctrl;
if (ctrl->l2_persistence == PRI_L2_PERSISTENCE_KEEP_UP) {
/*
* For PTP links:
* This is where we act a bit like L3 instead of L2, since we've
* got an L3 that depends on us keeping L2 automatically alive
* and happy.
*
* For PTMP links:
* We can optionally keep L2 automatically alive and happy.
*/
restart_timer_start(link);
}
if (PTP_MODE(ctrl)) {
switch (link->state) {
case Q921_MULTI_FRAME_ESTABLISHED:
case Q921_TIMER_RECOVERY:
/* Notify the upper layer that layer 2 went down. */
ctrl->schedev = 1;
ctrl->ev.gen.e = PRI_EVENT_DCHAN_DOWN;
ev = &ctrl->ev;
break;
default:
ev = NULL;
break;
}
} else {
ev = NULL;
}
return ev;
}
/*!
* \brief Bring all layer 2 links up.
*
* \param ctrl D channel controller.
*
* \return Nothing
*/
void q921_bring_layer2_up(struct pri *ctrl)
{
struct q921_link *link;
if (PTMP_MODE(ctrl)) {
/* Don't start with the broadcast link. */
link = ctrl->link.next;
} else {
link = &ctrl->link;
}
for (; link; link = link->next) {
if (!link->restart_timer) {
/* A restart on the link is not already in the works. */
kick_start_link(link);
}
}
}
/* This is the equivalent of the I-Frame queued up path in Figure B.7 in MULTI_FRAME_ESTABLISHED */
static int q921_send_queued_iframes(struct q921_link *link)
{
struct pri *ctrl;
struct q921_frame *f;
int frames_txd = 0;
ctrl = link->ctrl;
for (f = link->tx_queue; f; f = f->next) {
if (f->status != Q921_TX_FRAME_SENT) {
/* This frame needs to be sent. */
break;
}
}
if (!f) {
/* The Tx queue has no pending frames. */
return 0;
}
if (link->peer_rx_busy) {
/* Don't flood debug trace if not really looking at Q.921 layer. */
if (ctrl->debug & (/* PRI_DEBUG_Q921_STATE | */ PRI_DEBUG_Q921_DUMP)) {
pri_message(ctrl,
"TEI=%d Couldn't transmit I-frame at this time due to peer busy condition\n",
link->tei);
}
return 0;
}
if (link->v_s == Q921_ADD(link->v_a, ctrl->timers[PRI_TIMER_K])) {
/* Don't flood debug trace if not really looking at Q.921 layer. */
if (ctrl->debug & (/* PRI_DEBUG_Q921_STATE | */ PRI_DEBUG_Q921_DUMP)) {
pri_message(ctrl,
"TEI=%d Couldn't transmit I-frame at this time due to window shut\n",
link->tei);
}
return 0;
}
/* Send all pending frames that fit in the window. */
for (; f; f = f->next) {
if (link->v_s == Q921_ADD(link->v_a, ctrl->timers[PRI_TIMER_K])) {
/* The window is no longer open. */
break;
}
/* Send it now... */
switch (f->status) {
case Q921_TX_FRAME_NEVER_SENT:
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl,
"TEI=%d Transmitting N(S)=%d, window is open V(A)=%d K=%d\n",
link->tei, link->v_s, link->v_a, ctrl->timers[PRI_TIMER_K]);
}
break;
case Q921_TX_FRAME_PUSHED_BACK:
if (f->h.n_s != link->v_s) {
/* Should never happen. */
pri_error(ctrl,
"TEI=%d Retransmitting frame with old N(S)=%d as N(S)=%d!\n",
link->tei, f->h.n_s, link->v_s);
} else if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl, "TEI=%d Retransmitting frame N(S)=%d now!\n",
link->tei, link->v_s);
}
break;
default:
/* Should never happen. */
pri_error(ctrl, "Unexpected Tx Q frame status: %d", f->status);
break;
}
/*
* 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 = link->tei;
f->h.n_s = link->v_s;
f->h.n_r = link->v_r;
f->h.ft = 0;
f->h.p_f = 0;
q921_transmit(ctrl, (q921_h *) (&f->h), f->len);
Q921_INC(link->v_s);
++frames_txd;
if ((ctrl->debug & PRI_DEBUG_Q931_DUMP)
&& f->status == Q921_TX_FRAME_NEVER_SENT) {
/*
* The transmit operation might dump the Q.921 header, so logging
* the Q.931 message body after the transmit puts the sections of
* the message in the right order in the log.
*
* Also dump the Q.931 part only once instead of for every
* retransmission.
*/
q931_dump(ctrl, link->tei, (q931_h *) f->h.data, f->len - 4, 1);
}
f->status = Q921_TX_FRAME_SENT;
}
if (frames_txd) {
link->acknowledge_pending = 0;
if (!link->t200_timer) {
stop_t203(link);
start_t200(link);
}
}
return frames_txd;
}
static void q921_reject(struct q921_link *link, int pf)
{
q921_h h;
struct pri *ctrl;
ctrl = link->ctrl;
Q921_CLEAR_INIT(&h, link->sapi, link->tei);
h.s.x0 = 0; /* Always 0 */
h.s.ss = 2; /* Reject */
h.s.ft = 1; /* Frametype (01) */
h.s.n_r = link->v_r; /* Where to start retransmission N(R) */
h.s.p_f = pf;
switch (ctrl->localtype) {
case PRI_NETWORK:
h.h.c_r = 0;
break;
case PRI_CPE:
h.h.c_r = 1;
break;
default:
pri_error(ctrl, "Don't know how to REJ on a type %d node\n", ctrl->localtype);
return;
}
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl, "TEI=%d Sending REJ N(R)=%d\n", link->tei, link->v_r);
}
q921_transmit(ctrl, &h, 4);
}
static void q921_rr(struct q921_link *link, int pbit, int cmd)
{
q921_h h;
struct pri *ctrl;
ctrl = link->ctrl;
Q921_CLEAR_INIT(&h, link->sapi, link->tei);
h.s.x0 = 0; /* Always 0 */
h.s.ss = 0; /* Receive Ready */
h.s.ft = 1; /* Frametype (01) */
h.s.n_r = link->v_r; /* N(R) */
h.s.p_f = pbit; /* Poll/Final set appropriately */
switch (ctrl->localtype) {
case PRI_NETWORK:
if (cmd)
h.h.c_r = 1;
else
h.h.c_r = 0;
break;
case PRI_CPE:
if (cmd)
h.h.c_r = 0;
else
h.h.c_r = 1;
break;
default:
pri_error(ctrl, "Don't know how to RR on a type %d node\n", ctrl->localtype);
return;
}
#if 0 /* Don't flood debug trace with RR if not really looking at Q.921 layer. */
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl, "TEI=%d Sending RR N(R)=%d\n", link->tei, link->v_r);
}
#endif
q921_transmit(ctrl, &h, 4);
}
static void transmit_enquiry(struct q921_link *link)
{
if (!link->own_rx_busy) {
q921_rr(link, 1, 1);
link->acknowledge_pending = 0;
start_t200(link);
} else {
/* XXX: Implement me... */
}
}
static void t200_expire(void *vlink)
{
struct q921_link *link = vlink;
struct pri *ctrl;
ctrl = link->ctrl;
if (ctrl->debug & PRI_DEBUG_Q921_DUMP) {
pri_message(ctrl, "%s\n", __FUNCTION__);
q921_dump_pri(link, ' ');
}
link->t200_timer = 0;
switch (link->state) {
case Q921_MULTI_FRAME_ESTABLISHED:
link->RC = 0;
transmit_enquiry(link);
link->RC++;
q921_setstate(link, Q921_TIMER_RECOVERY);
break;
case Q921_TIMER_RECOVERY:
/* SDL Flow Figure B.8/Q.921 Page 81 */
if (link->RC != ctrl->timers[PRI_TIMER_N200]) {
#if 0
if (link->v_s == link->v_a) {
transmit_enquiry(link);
}
#else
/* We are chosing to enquiry by default (to reduce risk of T200 timer errors at the other
* side, instead of retransmission of the last I-frame we sent */
transmit_enquiry(link);
#endif
link->RC++;
} else {
q921_mdl_error(link, 'I');
q921_establish_data_link(link);
link->l3_initiated = 0;
q921_setstate(link, Q921_AWAITING_ESTABLISHMENT);
if (PTP_MODE(ctrl)) {
ctrl->schedev = 1;
ctrl->ev.gen.e = PRI_EVENT_DCHAN_DOWN;
}
}
break;
case Q921_AWAITING_ESTABLISHMENT:
if (link->RC != ctrl->timers[PRI_TIMER_N200]) {
link->RC++;
q921_send_sabme(link);
start_t200(link);
} else {
q921_check_delay_restart(link);
q921_discard_iqueue(link);
q921_mdl_error(link, 'G');
q921_setstate(link, Q921_TEI_ASSIGNED);
/* DL-RELEASE indication */
q931_dl_event(link, Q931_DL_EVENT_DL_RELEASE_IND);
}
break;
case Q921_AWAITING_RELEASE:
if (link->RC != ctrl->timers[PRI_TIMER_N200]) {
++link->RC;
q921_send_disc(link, 1);
start_t200(link);
} else {
q921_check_delay_restart(link);
q921_mdl_error(link, 'H');
/* DL-RELEASE confirm */
q931_dl_event(link, Q931_DL_EVENT_DL_RELEASE_CONFIRM);
q921_setstate(link, Q921_TEI_ASSIGNED);
}
break;
default:
/* Looks like someone forgot to stop the T200 timer. */
pri_error(ctrl, "T200 expired in state %d(%s)\n",
link->state, q921_state2str(link->state));
break;
}
}
/* This is sending a DL-UNIT-DATA request */
int q921_transmit_uiframe(struct q921_link *link, void *buf, int len)
{
uint8_t ubuf[512];
q921_h *h = (void *)&ubuf[0];
struct pri *ctrl;
ctrl = link->ctrl;
if (len >= 512) {
pri_error(ctrl, "Requested to send UI-frame larger than 512 bytes!\n");
return -1;
}
memset(ubuf, 0, sizeof(ubuf));
h->h.sapi = 0;
h->h.ea1 = 0;
h->h.ea2 = 1;
h->h.tei = link->tei;
h->u.m3 = 0;
h->u.m2 = 0;
h->u.p_f = 0; /* Poll bit set */
h->u.ft = Q921_FRAMETYPE_U;
switch (ctrl->localtype) {
case PRI_NETWORK:
h->h.c_r = 1;
break;
case PRI_CPE:
h->h.c_r = 0;
break;
default:
pri_error(ctrl, "Don't know how to UI-frame on a type %d node\n", ctrl->localtype);
return -1;
}
memcpy(h->u.data, buf, len);
q921_transmit(ctrl, h, len + 3);
return 0;
}
static struct q921_link *pri_find_tei(struct pri *ctrl, int sapi, int tei)
{
struct q921_link *link;
for (link = &ctrl->link; link; link = link->next) {
if (link->tei == tei && link->sapi == sapi)
return link;
}
return NULL;
}
/* This is the equivalent of a DL-DATA request, as well as the I-frame queued up outcome */
int q921_transmit_iframe(struct q921_link *link, void *buf, int len, int cr)
{
struct q921_frame *f, *prev=NULL;
struct pri *ctrl;
ctrl = link->ctrl;
if (PTMP_MODE(ctrl)) {
if (link->tei == Q921_TEI_GROUP) {
pri_error(ctrl, "Huh?! For PTMP, we shouldn't be sending I-frames out the group TEI\n");
return 0;
}
if (BRI_TE_PTMP(ctrl)) {
switch (link->state) {
case Q921_TEI_UNASSIGNED:
q921_setstate(link, Q921_ESTABLISH_AWAITING_TEI);
q921_tei_request(link);
break;
case Q921_ASSIGN_AWAITING_TEI:
q921_setstate(link, Q921_ESTABLISH_AWAITING_TEI);
break;
default:
break;
}
}
} else {
/* PTP modes, which shouldn't have subs */
}
/* Figure B.7/Q.921 Page 70 */
switch (link->state) {
case Q921_TEI_ASSIGNED:
/* If we aren't in a state compatiable with DL-DATA requests, start getting us there here */
restart_timer_stop(link);
q921_establish_data_link(link);
link->l3_initiated = 1;
q921_setstate(link, Q921_AWAITING_ESTABLISHMENT);
/* For all rest, we've done the work to get us up prior to this and fall through */
case Q921_ESTABLISH_AWAITING_TEI:
case Q921_TIMER_RECOVERY:
case Q921_AWAITING_ESTABLISHMENT:
case Q921_MULTI_FRAME_ESTABLISHED:
/* Find queue tail. */
for (f = link->tx_queue; f; f = f->next) {
prev = f;
}
f = calloc(1, sizeof(struct q921_frame) + len + 2);
if (f) {
Q921_INIT(&f->h, link->sapi, link->tei);
switch (ctrl->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;
}
/* Put new frame on queue tail. */
f->next = NULL;
f->status = Q921_TX_FRAME_NEVER_SENT;
f->len = len + 4;
memcpy(f->h.data, buf, len);
if (prev)
prev->next = f;
else
link->tx_queue = f;
if (link->state != Q921_MULTI_FRAME_ESTABLISHED) {
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl,
"TEI=%d Just queued I-frame since in state %d(%s)\n",
link->tei,
link->state, q921_state2str(link->state));
}
break;
}
if (link->peer_rx_busy) {
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl,
"TEI=%d Just queued I-frame due to peer busy condition\n",
link->tei);
}
break;
}
if (!q921_send_queued_iframes(link)) {
/*
* No frames sent even though we just put a frame on the queue.
*
* Special debug message/test here because we want to say what
* happened to the Q.931 message just queued but we don't want
* to flood the debug trace if we are not really looking at the
* Q.921 layer.
*/
if ((ctrl->debug & (PRI_DEBUG_Q921_STATE | PRI_DEBUG_Q921_DUMP))
== PRI_DEBUG_Q921_STATE) {
pri_message(ctrl, "TEI=%d Just queued I-frame due to window shut\n",
link->tei);
}
}
} else {
pri_error(ctrl, "!! Out of memory for Q.921 transmit\n");
return -1;
}
break;
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",
link->state, q921_state2str(link->state));
break;
}
return 0;
}
static void t203_expire(void *vlink)
{
struct q921_link *link = vlink;
struct pri *ctrl;
ctrl = link->ctrl;
if (ctrl->debug & PRI_DEBUG_Q921_DUMP)
pri_message(ctrl, "%s\n", __FUNCTION__);
link->t203_timer = 0;
switch (link->state) {
case Q921_MULTI_FRAME_ESTABLISHED:
transmit_enquiry(link);
link->RC = 0;
q921_setstate(link, Q921_TIMER_RECOVERY);
break;
default:
/* Looks like someone forgot to stop the T203 timer. */
pri_error(ctrl, "T203 expired in state %d(%s)\n",
link->state, q921_state2str(link->state));
break;
}
}
static void q921_dump_iqueue_info(struct q921_link *link)
{
struct pri *ctrl;
struct q921_frame *f;
int pending = 0;
int unacked = 0;
ctrl = link->ctrl;
for (f = link->tx_queue; f; f = f->next) {
if (f->status == Q921_TX_FRAME_SENT) {
unacked++;
} else {
pending++;
}
}
pri_error(ctrl, "Number of pending packets %d, sent but unacked %d\n", pending, unacked);
}
static void q921_dump_pri_by_h(struct pri *ctrl, char direction_tag, q921_h *h);
void q921_dump(struct pri *ctrl, q921_h *h, int len, int debugflags, int txrx)
{
int x;
const char *type;
char direction_tag;
direction_tag = txrx ? '>' : '<';
pri_message(ctrl, "\n");
if (debugflags & PRI_DEBUG_Q921_DUMP) {
q921_dump_pri_by_h(ctrl, direction_tag, h);
}
if (debugflags & PRI_DEBUG_Q921_RAW) {
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(ctrl, "%c [ %s]\n", direction_tag, buf);
free(buf);
}
}
if (debugflags & PRI_DEBUG_Q921_DUMP) {
switch (h->h.data[0] & Q921_FRAMETYPE_MASK) {
case 0:
case 2:
pri_message(ctrl, "%c Informational frame:\n", direction_tag);
break;
case 1:
pri_message(ctrl, "%c Supervisory frame:\n", direction_tag);
break;
case 3:
pri_message(ctrl, "%c Unnumbered frame:\n", direction_tag);
break;
}
pri_message(ctrl, "%c SAPI: %02d C/R: %d EA: %d\n",
direction_tag,
h->h.sapi,
h->h.c_r,
h->h.ea1);
pri_message(ctrl, "%c TEI: %03d EA: %d\n",
direction_tag,
h->h.tei,
h->h.ea2);
switch (h->h.data[0] & Q921_FRAMETYPE_MASK) {
case 0:
case 2:
/* Informational frame */
pri_message(ctrl, "%c N(S): %03d 0: %d\n",
direction_tag,
h->i.n_s,
h->i.ft);
pri_message(ctrl, "%c N(R): %03d P: %d\n",
direction_tag,
h->i.n_r,
h->i.p_f);
pri_message(ctrl, "%c %d bytes of data\n",
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(ctrl, "%c Zero: %d S: %d 01: %d [ %s ]\n",
direction_tag,
h->s.x0,
h->s.ss,
h->s.ft,
type);
pri_message(ctrl, "%c N(R): %03d P/F: %d\n",
direction_tag,
h->s.n_r,
h->s.p_f);
pri_message(ctrl, "%c %d bytes of data\n",
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;
default:
break;
}
}
pri_message(ctrl, "%c M3: %d P/F: %d M2: %d 11: %d [ %s ]\n",
direction_tag,
h->u.m3,
h->u.p_f,
h->u.m2,
h->u.ft,
type);
pri_message(ctrl, "%c %d bytes of data\n",
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;
u_int8_t *action;
/* TEI management related */
type = q921_tei_mgmt2str(h->u.data[3]);
pri_message(ctrl, "%c MDL Message: %d(%s)\n", direction_tag, h->u.data[3], type);
ri = (h->u.data[1] << 8) | h->u.data[2];
pri_message(ctrl, "%c Ri: %d\n", direction_tag, ri);
action = &h->u.data[4];
for (x = len - (action - (u_int8_t *) h); 0 < x; --x, ++action) {
pri_message(ctrl, "%c Ai: %d E:%d\n",
direction_tag, (*action >> 1) & 0x7f, *action & 0x01);
}
}
}
}
static void q921_dump_pri(struct q921_link *link, char direction_tag)
{
struct pri *ctrl;
ctrl = link->ctrl;
pri_message(ctrl, "%c TEI: %d State %d(%s)\n",
direction_tag, link->tei, link->state, q921_state2str(link->state));
pri_message(ctrl, "%c V(A)=%d, V(S)=%d, V(R)=%d\n",
direction_tag, link->v_a, link->v_s, link->v_r);
pri_message(ctrl, "%c K=%d, RC=%d, l3_initiated=%d, reject_except=%d, ack_pend=%d\n",
direction_tag, ctrl->timers[PRI_TIMER_K], link->RC, link->l3_initiated,
link->reject_exception, link->acknowledge_pending);
pri_message(ctrl, "%c T200_id=%d, N200=%d, T203_id=%d\n",
direction_tag, link->t200_timer, ctrl->timers[PRI_TIMER_N200], link->t203_timer);
}
static void q921_dump_pri_by_h(struct pri *ctrl, char direction_tag, q921_h *h)
{
struct q921_link *link;
if (!ctrl) {
return;
}
if (BRI_NT_PTMP(ctrl)) {
link = pri_find_tei(ctrl, h->h.sapi, h->h.tei);
} else if (BRI_TE_PTMP(ctrl)) {
/* We're operating on the specific TEI link */
link = ctrl->link.next;
} else {
link = &ctrl->link;
}
if (link) {
q921_dump_pri(link, direction_tag);
} else {
pri_message(ctrl, "%c Link not found for this frame.\n", direction_tag);
}
}
#define Q921_TEI_CHECK_MAX_POLLS 2
static void t201_expire(void *vctrl)
{
struct pri *ctrl;
struct q921_link *link;
struct q921_link *link_next;
ctrl = vctrl;
/* Start the TEI check timer. */
ctrl->t201_timer =
pri_schedule_event(ctrl, ctrl->timers[PRI_TIMER_T201], t201_expire, ctrl);
++ctrl->t201_expirycnt;
if (Q921_TEI_CHECK_MAX_POLLS < ctrl->t201_expirycnt) {
pri_schedule_del(ctrl, ctrl->t201_timer);
ctrl->t201_timer = 0;
/* Reclaim any dead TEI links. */
for (link = ctrl->link.next; link; link = link_next) {
link_next = link->next;
switch (link->tei_check) {
case Q921_TEI_CHECK_DEAD:
link->tei_check = Q921_TEI_CHECK_NONE;
q921_tei_remove(ctrl, link->tei);
q921_mdl_destroy(link);
break;
default:
link->tei_check = Q921_TEI_CHECK_NONE;
break;
}
}
return;
}
if (!ctrl->t201_timer) {
pri_error(ctrl, "Could not start T201 timer.");
/* Abort the remaining TEI check. */
for (link = ctrl->link.next; link; link = link->next) {
link->tei_check = Q921_TEI_CHECK_NONE;
}
return;
}
if (ctrl->t201_expirycnt == 1) {
/* First poll. Setup TEI check state. */
for (link = ctrl->link.next; link; link = link->next) {
if (link->state < Q921_TEI_ASSIGNED) {
/* We do not have a TEI. */
link->tei_check = Q921_TEI_CHECK_NONE;
} else {
/* Mark TEI as dead until proved otherwise. */
link->tei_check = Q921_TEI_CHECK_DEAD;
}
}
} else {
/* Subsequent polls. Setup for new TEI check poll. */
for (link = ctrl->link.next; link; link = link->next) {
switch (link->tei_check) {
case Q921_TEI_CHECK_REPLY:
link->tei_check = Q921_TEI_CHECK_DEAD_REPLY;
break;
default:
break;
}
}
}
q921_mdl_send(ctrl, Q921_TEI_IDENTITY_CHECK_REQUEST, 0, Q921_TEI_GROUP, 1);
}
static void q921_tei_check(struct pri *ctrl)
{
if (ctrl->t201_timer) {
/* TEI check procedure already in progress. Do not disturb it. */
return;
}
ctrl->t201_expirycnt = 0;
t201_expire(ctrl);
}
static void q921_mdl_ignore(struct pri *ctrl, q921_u *h, const char *reason)
{
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
/*
* Send out this message in debug modes since it is possible the
* user has misconfigured their link for the wrong mode.
*/
pri_message(ctrl, "Ignoring MDL message: %d(%s) %s\n",
h->data[3], q921_tei_mgmt2str(h->data[3]), reason);
}
}
static pri_event *q921_mdl_receive(struct pri *ctrl, q921_u *h, int len)
{
int ri;
struct q921_link *sub;
struct q921_link *link;
pri_event *res = NULL;
u_int8_t *action;
int count;
int tei;
if (len <= &h->data[0] - (u_int8_t *) h) {
pri_error(ctrl, "Received short MDL frame\n");
return NULL;
}
if (h->data[0] != 0x0f) {
pri_error(ctrl, "Received MDL with unsupported management entity %02x\n",
h->data[0]);
return NULL;
}
if (len <= &h->data[4] - (u_int8_t *) h) {
pri_error(ctrl, "Received short MDL message\n");
return NULL;
}
if (h->data[3] != Q921_TEI_IDENTITY_CHECK_RESPONSE
&& !(h->data[4] & 0x01)) {
pri_error(ctrl, "Received MDL message: %d(%s) with Ai E bit not set.\n",
h->data[3], q921_tei_mgmt2str(h->data[3]));
return NULL;
}
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl, "Received MDL message: %d(%s)\n",
h->data[3], q921_tei_mgmt2str(h->data[3]));
}
if (PTP_MODE(ctrl) && NT_MODE(ctrl)) {
/*
* We are not managing automatic TEI's in this mode so we can
* ignore MDL messages from the CPE.
*/
q921_mdl_ignore(ctrl, h, "We are in NT-PTP mode.");
return NULL;
}
ri = (h->data[1] << 8) | h->data[2];
tei = (h->data[4] >> 1);
switch (h->data[3]) {
case Q921_TEI_IDENTITY_REQUEST:
if (!BRI_NT_PTMP(ctrl)) {
q921_mdl_ignore(ctrl, h, "We are not in NT-PTMP mode.");
return NULL;
}
if (tei != Q921_TEI_GROUP) {
pri_error(ctrl, "Received %s with invalid TEI %d\n",
q921_tei_mgmt2str(Q921_TEI_IDENTITY_REQUEST), tei);
q921_mdl_send(ctrl, Q921_TEI_IDENTITY_DENIED, ri, tei, 1);
return NULL;
}
/* Find a TEI that is not allocated. */
tei = Q921_TEI_AUTO_FIRST;
do {
for (sub = &ctrl->link; sub->next; sub = sub->next) {
if (sub->next->tei == tei) {
/* This TEI is already assigned, try next one. */
++tei;
if (tei <= Q921_TEI_AUTO_LAST) {
break;
}
pri_error(ctrl, "TEI pool exhausted. Reclaiming dead TEIs.\n");
q921_mdl_send(ctrl, Q921_TEI_IDENTITY_DENIED, ri, Q921_TEI_GROUP, 1);
q921_tei_check(ctrl);
return NULL;
}
}
} while (sub->next);
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl, "Allocating new TEI %d\n", tei);
}
link = pri_link_new(ctrl, Q921_SAPI_CALL_CTRL, tei);
if (!link) {
pri_error(ctrl, "Unable to allocate layer 2 link for new TEI %d\n", tei);
return NULL;
}
sub->next = link;
q921_setstate(link, Q921_TEI_ASSIGNED);
q921_mdl_send(ctrl, Q921_TEI_IDENTITY_ASSIGNED, ri, tei, 1);
count = 0;
for (sub = ctrl->link.next; sub; sub = sub->next) {
++count;
}
if (Q921_TEI_AUTO_LAST - Q921_TEI_AUTO_FIRST + 1 <= count) {
/*
* We just allocated the last TEI. Try to reclaim dead TEIs
* before another is requested.
*/
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl, "Allocated last TEI. Reclaiming dead TEIs.\n");
}
q921_tei_check(ctrl);
}
if (ctrl->l2_persistence == PRI_L2_PERSISTENCE_KEEP_UP) {
/*
* Layer 2 is persistent so give the peer some time to setup
* it's new TEI and bring the link up itself before we bring the
* link up.
*/
restart_timer_start(link);
}
break;
case Q921_TEI_IDENTITY_CHECK_RESPONSE:
if (!BRI_NT_PTMP(ctrl)) {
/* Silently ignore the message since we never asked for the check. */
return NULL;
}
/* For each TEI listed in the message */
action = &h->data[4];
len -= (action - (u_int8_t *) h);
for (; len; --len, ++action) {
if (*action & 0x01) {
/* This is the last TEI in the list because the Ai E bit is set. */
len = 1;
}
tei = (*action >> 1);
if (tei == Q921_TEI_GROUP) {
pri_error(ctrl, "Received %s with invalid TEI %d\n",
q921_tei_mgmt2str(Q921_TEI_IDENTITY_CHECK_RESPONSE), tei);
continue;
}
for (sub = ctrl->link.next; sub; sub = sub->next) {
if (sub->tei == tei) {
/* Found the TEI. */
switch (sub->tei_check) {
case Q921_TEI_CHECK_NONE:
break;
case Q921_TEI_CHECK_DEAD:
case Q921_TEI_CHECK_DEAD_REPLY:
sub->tei_check = Q921_TEI_CHECK_REPLY;
break;
case Q921_TEI_CHECK_REPLY:
/* Duplicate TEI detected. */
sub->tei_check = Q921_TEI_CHECK_NONE;
q921_tei_remove(ctrl, tei);
q921_mdl_destroy(sub);
break;
}
break;
}
}
if (!sub) {
/* TEI not found. */
q921_tei_remove(ctrl, tei);
}
}
break;
case Q921_TEI_IDENTITY_VERIFY:
if (!BRI_NT_PTMP(ctrl)) {
q921_mdl_ignore(ctrl, h, "We are not in NT-PTMP mode.");
return NULL;
}
if (tei == Q921_TEI_GROUP) {
pri_error(ctrl, "Received %s with invalid TEI %d\n",
q921_tei_mgmt2str(Q921_TEI_IDENTITY_VERIFY), tei);
return NULL;
}
q921_tei_check(ctrl);
break;
case Q921_TEI_IDENTITY_ASSIGNED:
if (NT_MODE(ctrl)) {
/* We should not be receiving this message. */
q921_mdl_ignore(ctrl, h, "We are the network.");
return NULL;
}
if (!BRI_TE_PTMP(ctrl)) {
/*
* Silently ignore the message. It must not be for us
* since we will never ask for one.
*/
return NULL;
}
/* We're operating on the specific TEI link here */
link = ctrl->link.next;
switch (link->state) {
case Q921_TEI_UNASSIGNED:
/*
* We do not have a TEI and we are not currently asking for one.
* Start asking for one.
*/
q921_setstate(link, Q921_ASSIGN_AWAITING_TEI);
q921_tei_request(link);
return NULL;
case Q921_ASSIGN_AWAITING_TEI:
case Q921_ESTABLISH_AWAITING_TEI:
/* We do not have a TEI and we want one. */
break;
default:
/* We already have a TEI. */
if (tei == link->tei) {
/*
* The TEI assignment conflicts with ours. Our TEI is the
* duplicate so we should remove it. Q.921 Section 5.3.4.2
* condition c.
*/
pri_error(ctrl, "TEI=%d Conflicting TEI assignment. Removing our TEI.\n",
tei);
q921_mdl_remove(link);
q921_start(link);
}
return NULL;
}
if (ri != link->ri) {
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl,
"TEI assignment received for another Ri %02x (ours is %02x)\n",
ri, link->ri);
}
return NULL;
}
pri_schedule_del(ctrl, link->t202_timer);
link->t202_timer = 0;
link->tei = tei;
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl, "Got assigned TEI %d\n", tei);
}
switch (link->state) {
case Q921_ASSIGN_AWAITING_TEI:
q921_setstate(link, Q921_TEI_ASSIGNED);
if (ctrl->l2_persistence != PRI_L2_PERSISTENCE_KEEP_UP) {
ctrl->ev.gen.e = PRI_EVENT_DCHAN_UP;
res = &ctrl->ev;
break;
}
/* Fall through: Layer 2 is persistent so bring it up. */
case Q921_ESTABLISH_AWAITING_TEI:
q921_establish_data_link(link);
link->l3_initiated = 1;
q921_setstate(link, Q921_AWAITING_ESTABLISHMENT);
ctrl->ev.gen.e = PRI_EVENT_DCHAN_UP;
res = &ctrl->ev;
break;
default:
break;
}
break;
case Q921_TEI_IDENTITY_CHECK_REQUEST:
if (NT_MODE(ctrl)) {
/* We should not be receiving this message. */
q921_mdl_ignore(ctrl, h, "We are the network.");
return NULL;
}
if (PTP_MODE(ctrl)) {
/*
* Some telco switches/devices get very unhappy if we don't
* respond to the TEI check request with our permanently
* assigned TEI.
*/
link = &ctrl->link;
} else if (BRI_TE_PTMP(ctrl)) {
/* We're operating on the specific TEI link here */
link = ctrl->link.next;
if (link->state < Q921_TEI_ASSIGNED) {
/* We do not have a TEI. */
return NULL;
}
} else {
/* Should never get here. */
return NULL;
}
/* If it's addressed to the group TEI or to our TEI specifically, we respond */
if (tei == Q921_TEI_GROUP || tei == link->tei) {
q921_mdl_send(ctrl, Q921_TEI_IDENTITY_CHECK_RESPONSE, random() % 65535, link->tei, 1);
}
break;
case Q921_TEI_IDENTITY_REMOVE:
if (NT_MODE(ctrl)) {
/* We should not be receiving this message. */
q921_mdl_ignore(ctrl, h, "We are the network.");
return NULL;
}
if (!BRI_TE_PTMP(ctrl)) {
/*
* Silently ignore the message. If we are TE-PTP our
* TEI is permanently assigned and cannot be removed.
*/
return NULL;
}
/* We're operating on the specific TEI link here */
link = ctrl->link.next;
if (link->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 == link->tei) {
q921_mdl_remove(link);
q921_start(link);
}
break;
}
return res; /* Do we need to return something??? */
}
static int is_command(struct pri *ctrl, q921_h *h)
{
int command = 0;
int c_r = h->s.h.c_r;
if ((ctrl->localtype == PRI_NETWORK && c_r == 0) ||
(ctrl->localtype == PRI_CPE && c_r == 1))
command = 1;
return command;
}
static void q921_clear_exception_conditions(struct q921_link *link)
{
link->own_rx_busy = 0;
link->peer_rx_busy = 0;
link->reject_exception = 0;
link->acknowledge_pending = 0;
}
static pri_event *q921_sabme_rx(struct q921_link *link, q921_h *h)
{
pri_event *res = NULL;
struct pri *ctrl;
enum Q931_DL_EVENT delay_q931_dl_event;
ctrl = link->ctrl;
switch (link->state) {
case Q921_TIMER_RECOVERY:
/* Timer recovery state handling is same as multiframe established */
case Q921_MULTI_FRAME_ESTABLISHED:
/* Send Unnumbered Acknowledgement */
q921_send_ua(link, h->u.p_f);
q921_clear_exception_conditions(link);
q921_mdl_error(link, 'F');
if (link->v_s != link->v_a) {
q921_discard_iqueue(link);
/* DL-ESTABLISH indication */
delay_q931_dl_event = Q931_DL_EVENT_DL_ESTABLISH_IND;
} else {
delay_q931_dl_event = Q931_DL_EVENT_NONE;
}
stop_t200(link);
start_t203(link);
link->v_s = link->v_a = link->v_r = 0;
q921_setstate(link, Q921_MULTI_FRAME_ESTABLISHED);
if (delay_q931_dl_event != Q931_DL_EVENT_NONE) {
/* Delayed because Q.931 could send STATUS messages. */
q931_dl_event(link, delay_q931_dl_event);
}
break;
case Q921_TEI_ASSIGNED:
restart_timer_stop(link);
q921_send_ua(link, h->u.p_f);
q921_clear_exception_conditions(link);
link->v_s = link->v_a = link->v_r = 0;
/* DL-ESTABLISH indication */
delay_q931_dl_event = Q931_DL_EVENT_DL_ESTABLISH_IND;
if (PTP_MODE(ctrl)) {
ctrl->ev.gen.e = PRI_EVENT_DCHAN_UP;
res = &ctrl->ev;
}
start_t203(link);
q921_setstate(link, Q921_MULTI_FRAME_ESTABLISHED);
if (delay_q931_dl_event != Q931_DL_EVENT_NONE) {
/* Delayed because Q.931 could send STATUS messages. */
q931_dl_event(link, delay_q931_dl_event);
}
break;
case Q921_AWAITING_ESTABLISHMENT:
q921_send_ua(link, h->u.p_f);
break;
case Q921_AWAITING_RELEASE:
q921_send_dm(link, h->u.p_f);
break;
default:
pri_error(ctrl, "Cannot handle SABME in state %d(%s)\n",
link->state, q921_state2str(link->state));
break;
}
return res;
}
static pri_event *q921_disc_rx(struct q921_link *link, q921_h *h)
{
pri_event *res = NULL;
struct pri *ctrl;
ctrl = link->ctrl;
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl, "TEI=%d Got DISC\n", link->tei);
}
switch (link->state) {
case Q921_TEI_ASSIGNED:
case Q921_AWAITING_ESTABLISHMENT:
q921_send_dm(link, h->u.p_f);
break;
case Q921_AWAITING_RELEASE:
q921_send_ua(link, h->u.p_f);
break;
case Q921_MULTI_FRAME_ESTABLISHED:
case Q921_TIMER_RECOVERY:
res = q921_check_delay_restart(link);
q921_discard_iqueue(link);
q921_send_ua(link, h->u.p_f);
/* DL-RELEASE indication */
q931_dl_event(link, Q931_DL_EVENT_DL_RELEASE_IND);
stop_t200(link);
if (link->state == Q921_MULTI_FRAME_ESTABLISHED)
stop_t203(link);
q921_setstate(link, Q921_TEI_ASSIGNED);
break;
default:
pri_error(ctrl, "Don't know what to do with DISC in state %d(%s)\n",
link->state, q921_state2str(link->state));
break;
}
return res;
}
static void q921_mdl_remove(struct q921_link *link)
{
int mdl_free_me;
struct pri *ctrl;
ctrl = link->ctrl;
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl, "MDL-REMOVE: Removing TEI %d\n", link->tei);
}
if (BRI_NT_PTMP(ctrl)) {
if (link == &ctrl->link) {
pri_error(ctrl, "Bad bad bad! Cannot MDL-REMOVE master\n");
return;
}
mdl_free_me = 1;
} else {
mdl_free_me = 0;
}
switch (link->state) {
case Q921_TEI_ASSIGNED:
if (mdl_free_me) {
restart_timer_stop(link);
}
/* XXX: deviation! Since we don't have a UI queue, we just discard our I-queue */
q921_discard_iqueue(link);
q921_setstate(link, Q921_TEI_UNASSIGNED);
break;
case Q921_AWAITING_ESTABLISHMENT:
q921_discard_iqueue(link);
/* DL-RELEASE indication */
q931_dl_event(link, Q931_DL_EVENT_DL_RELEASE_IND);
stop_t200(link);
q921_setstate(link, Q921_TEI_UNASSIGNED);
break;
case Q921_AWAITING_RELEASE:
q921_discard_iqueue(link);
/* DL-RELEASE confirm */
q931_dl_event(link, Q931_DL_EVENT_DL_RELEASE_CONFIRM);
stop_t200(link);
q921_setstate(link, Q921_TEI_UNASSIGNED);
break;
case Q921_MULTI_FRAME_ESTABLISHED:
q921_discard_iqueue(link);
/* DL-RELEASE indication */
q931_dl_event(link, Q931_DL_EVENT_DL_RELEASE_IND);
stop_t200(link);
stop_t203(link);
q921_setstate(link, Q921_TEI_UNASSIGNED);
break;
case Q921_TIMER_RECOVERY:
q921_discard_iqueue(link);
/* DL-RELEASE indication */
q931_dl_event(link, Q931_DL_EVENT_DL_RELEASE_IND);
stop_t200(link);
q921_setstate(link, Q921_TEI_UNASSIGNED);
break;
default:
pri_error(ctrl, "MDL-REMOVE when in state %d(%s)\n",
link->state, q921_state2str(link->state));
return;
}
q931_dl_event(link, Q931_DL_EVENT_TEI_REMOVAL);
/*
* Negate the TEI value so debug messages will display a
* negated TEI when it is actually unassigned.
*/
link->tei = -link->tei;
link->mdl_free_me = mdl_free_me;
}
static void q921_mdl_link_destroy(struct q921_link *link)
{
struct pri *ctrl;
struct q921_link *freep;
struct q921_link *prev;
ctrl = link->ctrl;
freep = NULL;
for (prev = &ctrl->link; prev->next; prev = prev->next) {
if (prev->next == link) {
prev->next = link->next;
freep = link;
break;
}
}
if (freep == NULL) {
pri_error(ctrl, "Huh!? no match found in list for TEI %d\n", -link->tei);
return;
}
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl, "Freeing TEI of %d\n", -freep->tei);
}
pri_link_destroy(freep);
}
static void q921_mdl_destroy(struct q921_link *link)
{
q921_mdl_remove(link);
if (link->mdl_free_me) {
q921_mdl_link_destroy(link);
}
}
static void q921_mdl_handle_network_error(struct q921_link *link, char error)
{
struct pri *ctrl;
switch (error) {
case 'C':
case 'D':
case 'G':
case 'H':
q921_mdl_remove(link);
break;
case 'A':
case 'B':
case 'E':
case 'F':
case 'I':
case 'J':
case 'K':
break;
default:
ctrl = link->ctrl;
pri_error(ctrl, "Network MDL can't handle error of type %c\n", error);
break;
}
}
static void q921_mdl_handle_cpe_error(struct q921_link *link, char error)
{
struct pri *ctrl;
switch (error) {
case 'C':
case 'D':
case 'G':
case 'H':
q921_mdl_remove(link);
break;
case 'A':
case 'B':
case 'E':
case 'F':
case 'I':
case 'J':
case 'K':
break;
default:
ctrl = link->ctrl;
pri_error(ctrl, "CPE MDL can't handle error of type %c\n", error);
break;
}
}
static void q921_mdl_handle_ptp_error(struct q921_link *link, char error)
{
struct pri *ctrl;
ctrl = link->ctrl;
switch (error) {
case 'J':
/*
* This is for the transition to Q921_AWAITING_ESTABLISHMENT.
* The event is genereated here rather than where the MDL_ERROR
* 'J' is posted because of the potential event conflict with
* incoming I-frame information passed to Q.931.
*/
ctrl->schedev = 1;
ctrl->ev.gen.e = PRI_EVENT_DCHAN_DOWN;
break;
case 'A':
case 'B':
case 'C':
case 'D':
case 'E':
case 'F':
case 'G':
case 'H':
case 'I':
case 'K':
break;
default:
pri_error(ctrl, "PTP MDL can't handle error of type %c\n", error);
break;
}
}
static void q921_mdl_handle_error(struct q921_link *link, char error)
{
struct pri *ctrl;
ctrl = link->ctrl;
if (PTP_MODE(ctrl)) {
q921_mdl_handle_ptp_error(link, error);
} else {
if (ctrl->localtype == PRI_NETWORK) {
q921_mdl_handle_network_error(link, error);
} else {
q921_mdl_handle_cpe_error(link, error);
}
}
}
static void q921_mdl_handle_error_callback(void *vlink)
{
struct q921_link *link = vlink;
q921_mdl_handle_error(link, link->mdl_error);
link->mdl_error = 0;
link->mdl_timer = 0;
if (link->mdl_free_me) {
q921_mdl_link_destroy(link);
}
}
static void q921_mdl_error(struct q921_link *link, char error)
{
int is_debug_q921_state;
struct pri *ctrl;
ctrl = link->ctrl;
/* Log the MDL-ERROR event when detected. */
is_debug_q921_state = (ctrl->debug & PRI_DEBUG_Q921_STATE);
switch (error) {
case 'A':
pri_message(ctrl,
"TEI=%d MDL-ERROR (A): Got supervisory frame with F=1 in state %d(%s)\n",
link->tei, link->state, q921_state2str(link->state));
break;
case 'B':
case 'E':
pri_message(ctrl, "TEI=%d MDL-ERROR (%c): DM (F=%c) in state %d(%s)\n",
link->tei, error, (error == 'B') ? '1' : '0',
link->state, q921_state2str(link->state));
break;
case 'C':
case 'D':
if (is_debug_q921_state || PTP_MODE(ctrl)) {
pri_message(ctrl, "TEI=%d MDL-ERROR (%c): UA (F=%c) in state %d(%s)\n",
link->tei, error, (error == 'C') ? '1' : '0',
link->state, q921_state2str(link->state));
}
break;
case 'F':
/*
* The peer is restarting the link.
* Some reasons this might happen:
* 1) Our link establishment requests collided.
* 2) They got reset.
* 3) They could not talk to us for some reason because
* their T200 timer expired N200 times.
* 4) They got an MDL-ERROR (J).
*/
if (is_debug_q921_state) {
/*
* This message is rather annoying and is normal for
* reasons 1-3 above.
*/
pri_message(ctrl, "TEI=%d MDL-ERROR (F): SABME in state %d(%s)\n",
link->tei, link->state, q921_state2str(link->state));
}
break;
case 'G':
/* We could not get a response from the peer. */
if (is_debug_q921_state) {
pri_message(ctrl,
"TEI=%d MDL-ERROR (G): T200 expired N200 times sending SABME in state %d(%s)\n",
link->tei, link->state, q921_state2str(link->state));
}
break;
case 'H':
/* We could not get a response from the peer. */
if (is_debug_q921_state) {
pri_message(ctrl,
"TEI=%d MDL-ERROR (H): T200 expired N200 times sending DISC in state %d(%s)\n",
link->tei, link->state, q921_state2str(link->state));
}
break;
case 'I':
/* We could not get a response from the peer. */
if (is_debug_q921_state) {
pri_message(ctrl,
"TEI=%d MDL-ERROR (I): T200 expired N200 times sending RR/RNR in state %d(%s)\n",
link->tei, link->state, q921_state2str(link->state));
}
break;
case 'J':
/* N(R) not within ack window. */
pri_error(ctrl, "TEI=%d MDL-ERROR (J): N(R) error in state %d(%s)\n",
link->tei, link->state, q921_state2str(link->state));
break;
case 'K':
/*
* Received a frame reject frame.
* The other end does not like what we are doing at all for some reason.
*/
pri_error(ctrl, "TEI=%d MDL-ERROR (K): FRMR in state %d(%s)\n",
link->tei, link->state, q921_state2str(link->state));
break;
default:
pri_message(ctrl, "TEI=%d MDL-ERROR (%c): in state %d(%s)\n",
link->tei, error, link->state, q921_state2str(link->state));
break;
}
if (link->mdl_error) {
/* This should not happen. */
pri_error(ctrl,
"Trying to queue MDL-ERROR (%c) when MDL-ERROR (%c) is already scheduled\n",
error, link->mdl_error);
return;
}
link->mdl_error = error;
link->mdl_timer = pri_schedule_event(ctrl, 0, q921_mdl_handle_error_callback, link);
if (!link->mdl_timer) {
/* Timer allocation failed */
link->mdl_error = 0;
}
}
static pri_event *q921_ua_rx(struct q921_link *link, q921_h *h)
{
struct pri *ctrl;
pri_event *res = NULL;
enum Q931_DL_EVENT delay_q931_dl_event;
ctrl = link->ctrl;
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl, "TEI=%d Got UA\n", link->tei);
}
switch (link->state) {
case Q921_TEI_ASSIGNED:
case Q921_MULTI_FRAME_ESTABLISHED:
case Q921_TIMER_RECOVERY:
if (h->u.p_f) {
q921_mdl_error(link, 'C');
} else {
q921_mdl_error(link, 'D');
}
break;
case Q921_AWAITING_ESTABLISHMENT:
if (!h->u.p_f) {
q921_mdl_error(link, 'D');
break;
}
delay_q931_dl_event = Q931_DL_EVENT_NONE;
if (!link->l3_initiated) {
if (link->v_s != link->v_a) {
q921_discard_iqueue(link);
/* DL-ESTABLISH indication */
delay_q931_dl_event = Q931_DL_EVENT_DL_ESTABLISH_IND;
}
} else {
link->l3_initiated = 0;
/* DL-ESTABLISH confirm */
delay_q931_dl_event = Q931_DL_EVENT_DL_ESTABLISH_CONFIRM;
}
if (PTP_MODE(ctrl)) {
ctrl->ev.gen.e = PRI_EVENT_DCHAN_UP;
res = &ctrl->ev;
}
stop_t200(link);
start_t203(link);
link->v_r = link->v_s = link->v_a = 0;
q921_setstate(link, Q921_MULTI_FRAME_ESTABLISHED);
if (delay_q931_dl_event != Q931_DL_EVENT_NONE) {
/* Delayed because Q.931 could send STATUS messages. */
q931_dl_event(link, delay_q931_dl_event);
}
break;
case Q921_AWAITING_RELEASE:
if (!h->u.p_f) {
q921_mdl_error(link, 'D');
} else {
res = q921_check_delay_restart(link);
/* DL-RELEASE confirm */
q931_dl_event(link, Q931_DL_EVENT_DL_RELEASE_CONFIRM);
stop_t200(link);
q921_setstate(link, Q921_TEI_ASSIGNED);
}
break;
default:
pri_error(ctrl, "Don't know what to do with UA in state %d(%s)\n",
link->state, q921_state2str(link->state));
break;
}
return res;
}
static void q921_enquiry_response(struct q921_link *link)
{
struct pri *ctrl;
if (link->own_rx_busy) {
/* XXX : TODO later sometime */
ctrl = link->ctrl;
pri_error(ctrl, "Implement me %s: own_rx_busy\n", __FUNCTION__);
//q921_rnr(link);
} else {
q921_rr(link, 1, 0);
}
link->acknowledge_pending = 0;
}
static void n_r_error_recovery(struct q921_link *link)
{
q921_mdl_error(link, 'J');
q921_establish_data_link(link);
link->l3_initiated = 0;
}
static void update_v_a(struct q921_link *link, int n_r)
{
int idealcnt = 0, realcnt = 0;
int x;
struct pri *ctrl;
ctrl = link->ctrl;
/* Cancel each packet as necessary */
if (ctrl->debug & PRI_DEBUG_Q921_DUMP)
pri_message(ctrl, "-- Got ACK for N(S)=%d to (but not including) N(S)=%d\n", link->v_a, n_r);
for (x = link->v_a; x != n_r; Q921_INC(x)) {
idealcnt++;
realcnt += q921_ack_packet(link, x);
}
if (idealcnt != realcnt) {
pri_error(ctrl, "Ideally should have ack'd %d frames, but actually ack'd %d. This is not good.\n", idealcnt, realcnt);
q921_dump_iqueue_info(link);
}
link->v_a = n_r;
}
/*! \brief Is V(A) <= N(R) <= V(S) ? */
static int n_r_is_valid(struct q921_link *link, int n_r)
{
int x;
for (x = link->v_a; x != n_r && x != link->v_s; Q921_INC(x)) {
}
if (x != n_r) {
return 0;
} else {
return 1;
}
}
static int q921_invoke_retransmission(struct q921_link *link, int n_r);
static pri_event *timer_recovery_rr_rej_rx(struct q921_link *link, q921_h *h)
{
struct pri *ctrl;
ctrl = link->ctrl;
/* Figure B.7/Q.921 Page 74 */
link->peer_rx_busy = 0;
if (is_command(ctrl, h)) {
if (h->s.p_f) {
/* Enquiry response */
q921_enquiry_response(link);
}
if (n_r_is_valid(link, h->s.n_r)) {
update_v_a(link, h->s.n_r);
} else {
goto n_r_error_out;
}
} else {
if (!h->s.p_f) {
if (n_r_is_valid(link, h->s.n_r)) {
update_v_a(link, h->s.n_r);
} else {
goto n_r_error_out;
}
} else {
if (n_r_is_valid(link, h->s.n_r)) {
update_v_a(link, h->s.n_r);
stop_t200(link);
start_t203(link);
q921_invoke_retransmission(link, h->s.n_r);
q921_setstate(link, Q921_MULTI_FRAME_ESTABLISHED);
} else {
goto n_r_error_out;
}
}
}
return NULL;
n_r_error_out:
n_r_error_recovery(link);
q921_setstate(link, Q921_AWAITING_ESTABLISHMENT);
return NULL;
}
static pri_event *q921_rr_rx(struct q921_link *link, q921_h *h)
{
pri_event *res = NULL;
struct pri *ctrl;
ctrl = link->ctrl;
#if 0 /* Don't flood debug trace with RR if not really looking at Q.921 layer. */
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl, "TEI=%d Got RR N(R)=%d\n", link->tei, h->s.n_r);
}
#endif
switch (link->state) {
case Q921_TIMER_RECOVERY:
res = timer_recovery_rr_rej_rx(link, h);
break;
case Q921_MULTI_FRAME_ESTABLISHED:
/* Figure B.7/Q.921 Page 74 */
link->peer_rx_busy = 0;
if (is_command(ctrl, h)) {
if (h->s.p_f) {
/* Enquiry response */
q921_enquiry_response(link);
}
} else {
if (h->s.p_f) {
q921_mdl_error(link, 'A');
}
}
if (!n_r_is_valid(link, h->s.n_r)) {
n_r_error_recovery(link);
q921_setstate(link, Q921_AWAITING_ESTABLISHMENT);
} else {
if (h->s.n_r == link->v_s) {
update_v_a(link, h->s.n_r);
stop_t200(link);
start_t203(link);
} else {
if (h->s.n_r != link->v_a) {
/* Need to check the validity of n_r as well.. */
update_v_a(link, h->s.n_r);
restart_t200(link);
}
}
}
break;
case Q921_TEI_ASSIGNED:
case Q921_AWAITING_ESTABLISHMENT:
case Q921_AWAITING_RELEASE:
/*
* Ignore this frame.
* We likely got reset and the other end has not realized it yet.
*/
break;
default:
pri_error(ctrl, "Don't know what to do with RR in state %d(%s)\n",
link->state, q921_state2str(link->state));
break;
}
return res;
}
static int q921_invoke_retransmission(struct q921_link *link, int n_r)
{
struct q921_frame *f;
struct pri *ctrl;
ctrl = link->ctrl;
/*
* All acked frames should already have been removed from the queue.
* Push back all sent frames.
*/
for (f = link->tx_queue; f && f->status == Q921_TX_FRAME_SENT; f = f->next) {
f->status = Q921_TX_FRAME_PUSHED_BACK;
/* Sanity check: Is V(A) <= N(S) <= V(S)? */
if (!n_r_is_valid(link, f->h.n_s)) {
pri_error(ctrl,
"Tx Q frame with invalid N(S)=%d. Must be (V(A)=%d) <= N(S) <= (V(S)=%d)\n",
f->h.n_s, link->v_a, link->v_s);
}
}
link->v_s = n_r;
return q921_send_queued_iframes(link);
}
static pri_event *q921_rej_rx(struct q921_link *link, q921_h *h)
{
pri_event *res = NULL;
struct pri *ctrl;
ctrl = link->ctrl;
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl, "TEI=%d Got REJ N(R)=%d\n", link->tei, h->s.n_r);
}
switch (link->state) {
case Q921_TIMER_RECOVERY:
res = timer_recovery_rr_rej_rx(link, h);
break;
case Q921_MULTI_FRAME_ESTABLISHED:
/* Figure B.7/Q.921 Page 74 */
link->peer_rx_busy = 0;
if (is_command(ctrl, h)) {
if (h->s.p_f) {
/* Enquiry response */
q921_enquiry_response(link);
}
} else {
if (h->s.p_f) {
q921_mdl_error(link, 'A');
}
}
if (!n_r_is_valid(link, h->s.n_r)) {
n_r_error_recovery(link);
q921_setstate(link, Q921_AWAITING_ESTABLISHMENT);
} else {
update_v_a(link, h->s.n_r);
stop_t200(link);
start_t203(link);
q921_invoke_retransmission(link, h->s.n_r);
}
break;
case Q921_TEI_ASSIGNED:
case Q921_AWAITING_ESTABLISHMENT:
case Q921_AWAITING_RELEASE:
/*
* Ignore this frame.
* We likely got reset and the other end has not realized it yet.
*/
break;
default:
pri_error(ctrl, "Don't know what to do with REJ in state %d(%s)\n",
link->state, q921_state2str(link->state));
break;
}
return res;
}
static pri_event *q921_frmr_rx(struct q921_link *link, q921_h *h)
{
pri_event *res = NULL;
struct pri *ctrl;
ctrl = link->ctrl;
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl, "TEI=%d Got FRMR\n", link->tei);
}
switch (link->state) {
case Q921_TIMER_RECOVERY:
case Q921_MULTI_FRAME_ESTABLISHED:
q921_mdl_error(link, 'K');
q921_establish_data_link(link);
link->l3_initiated = 0;
q921_setstate(link, Q921_AWAITING_ESTABLISHMENT);
if (PTP_MODE(ctrl)) {
ctrl->ev.gen.e = PRI_EVENT_DCHAN_DOWN;
res = &ctrl->ev;
}
break;
case Q921_TEI_ASSIGNED:
case Q921_AWAITING_ESTABLISHMENT:
case Q921_AWAITING_RELEASE:
/*
* Ignore this frame.
* We likely got reset and the other end has not realized it yet.
*/
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl, "TEI=%d Ignoring FRMR.\n", link->tei);
}
break;
default:
pri_error(ctrl, "Don't know what to do with FRMR in state %d(%s)\n",
link->state, q921_state2str(link->state));
break;
}
return res;
}
static pri_event *q921_iframe_rx(struct q921_link *link, q921_h *h, int len)
{
struct pri *ctrl;
pri_event *eres = NULL;
int res = 0;
int delay_q931_receive;
ctrl = link->ctrl;
switch (link->state) {
case Q921_TIMER_RECOVERY:
case Q921_MULTI_FRAME_ESTABLISHED:
delay_q931_receive = 0;
/* FIXME: Verify that it's a command ... */
if (link->own_rx_busy) {
/* DEVIATION: Handle own rx busy */
} else if (h->i.n_s == link->v_r) {
Q921_INC(link->v_r);
link->reject_exception = 0;
/*
* Dump Q.931 message where Q.921 says to queue it to Q.931 so if
* Q.921 is dumping its frames they will be in the correct order.
*/
if (ctrl->debug & PRI_DEBUG_Q931_DUMP) {
q931_dump(ctrl, h->h.tei, (q931_h *) h->i.data, len - 4, 0);
}
delay_q931_receive = 1;
if (h->i.p_f) {
q921_rr(link, 1, 0);
link->acknowledge_pending = 0;
} else {
link->acknowledge_pending = 1;
}
} else {
if (link->reject_exception) {
if (h->i.p_f) {
q921_rr(link, 1, 0);
link->acknowledge_pending = 0;
}
} else {
link->reject_exception = 1;
q921_reject(link, h->i.p_f);
link->acknowledge_pending = 0;
}
}
if (!n_r_is_valid(link, h->i.n_r)) {
n_r_error_recovery(link);
q921_setstate(link, Q921_AWAITING_ESTABLISHMENT);
} else {
if (link->state == Q921_TIMER_RECOVERY) {
update_v_a(link, h->i.n_r);
} else {
if (link->peer_rx_busy) {
update_v_a(link, h->i.n_r);
} else {
if (h->i.n_r == link->v_s) {
update_v_a(link, h->i.n_r);
stop_t200(link);
start_t203(link);
} else {
if (h->i.n_r != link->v_a) {
update_v_a(link, h->i.n_r);
reschedule_t200(link);
}
}
}
}
}
if (delay_q931_receive) {
/* Q.921 has finished processing the frame so we can give it to Q.931 now. */
res = q931_receive(link, (q931_h *) h->i.data, len - 4);
if (res != -1 && (res & Q931_RES_HAVEEVENT)) {
eres = &ctrl->ev;
}
}
break;
case Q921_TEI_ASSIGNED:
case Q921_AWAITING_ESTABLISHMENT:
case Q921_AWAITING_RELEASE:
/*
* Ignore this frame.
* We likely got reset and the other end has not realized it yet.
*/
break;
default:
pri_error(ctrl, "Don't know what to do with an I-frame in state %d(%s)\n",
link->state, q921_state2str(link->state));
break;
}
return eres;
}
static pri_event *q921_dm_rx(struct q921_link *link, q921_h *h)
{
pri_event *res = NULL;
struct pri *ctrl;
ctrl = link->ctrl;
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl, "TEI=%d Got DM\n", link->tei);
}
switch (link->state) {
case Q921_TEI_ASSIGNED:
if (h->u.p_f)
break;
/* else */
restart_timer_stop(link);
q921_establish_data_link(link);
link->l3_initiated = 1;
q921_setstate(link, Q921_AWAITING_ESTABLISHMENT);
break;
case Q921_AWAITING_ESTABLISHMENT:
if (!h->u.p_f)
break;
res = q921_check_delay_restart(link);
q921_discard_iqueue(link);
/* DL-RELEASE indication */
q931_dl_event(link, Q931_DL_EVENT_DL_RELEASE_IND);
stop_t200(link);
q921_setstate(link, Q921_TEI_ASSIGNED);
break;
case Q921_AWAITING_RELEASE:
if (!h->u.p_f)
break;
res = q921_check_delay_restart(link);
/* DL-RELEASE confirm */
q931_dl_event(link, Q931_DL_EVENT_DL_RELEASE_CONFIRM);
stop_t200(link);
q921_setstate(link, Q921_TEI_ASSIGNED);
break;
case Q921_MULTI_FRAME_ESTABLISHED:
if (h->u.p_f) {
q921_mdl_error(link, 'B');
break;
}
q921_mdl_error(link, 'E');
q921_establish_data_link(link);
link->l3_initiated = 0;
q921_setstate(link, Q921_AWAITING_ESTABLISHMENT);
if (PTP_MODE(ctrl)) {
ctrl->ev.gen.e = PRI_EVENT_DCHAN_DOWN;
res = &ctrl->ev;
}
break;
case Q921_TIMER_RECOVERY:
if (h->u.p_f) {
q921_mdl_error(link, 'B');
} else {
q921_mdl_error(link, 'E');
}
q921_establish_data_link(link);
link->l3_initiated = 0;
q921_setstate(link, Q921_AWAITING_ESTABLISHMENT);
if (PTP_MODE(ctrl)) {
ctrl->ev.gen.e = PRI_EVENT_DCHAN_DOWN;
res = &ctrl->ev;
}
break;
default:
pri_error(ctrl, "Don't know what to do with DM frame in state %d(%s)\n",
link->state, q921_state2str(link->state));
break;
}
return res;
}
static pri_event *q921_rnr_rx(struct q921_link *link, q921_h *h)
{
pri_event *res = NULL;
struct pri *ctrl;
ctrl = link->ctrl;
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl, "TEI=%d Got RNR N(R)=%d\n", link->tei, h->s.n_r);
}
switch (link->state) {
case Q921_MULTI_FRAME_ESTABLISHED:
link->peer_rx_busy = 1;
if (!is_command(ctrl, h)) {
if (h->s.p_f) {
q921_mdl_error(link, 'A');
}
} else {
if (h->s.p_f) {
q921_enquiry_response(link);
}
}
if (!n_r_is_valid(link, h->s.n_r)) {
n_r_error_recovery(link);
q921_setstate(link, Q921_AWAITING_ESTABLISHMENT);
} else {
update_v_a(link, h->s.n_r);
stop_t203(link);
restart_t200(link);
}
break;
case Q921_TIMER_RECOVERY:
/* Q.921 Figure B.8 Q921 (Sheet 6 of 9) Page 85 */
link->peer_rx_busy = 1;
if (is_command(ctrl, h)) {
if (h->s.p_f) {
q921_enquiry_response(link);
}
if (n_r_is_valid(link, h->s.n_r)) {
update_v_a(link, h->s.n_r);
break;
} else {
n_r_error_recovery(link);
q921_setstate(link, Q921_AWAITING_ESTABLISHMENT);
break;
}
} else {
if (h->s.p_f) {
if (n_r_is_valid(link, h->s.n_r)) {
update_v_a(link, h->s.n_r);
restart_t200(link);
q921_invoke_retransmission(link, h->s.n_r);
q921_setstate(link, Q921_MULTI_FRAME_ESTABLISHED);
break;
} else {
n_r_error_recovery(link);
q921_setstate(link, Q921_AWAITING_ESTABLISHMENT);
break;
}
} else {
if (n_r_is_valid(link, h->s.n_r)) {
update_v_a(link, h->s.n_r);
break;
} else {
n_r_error_recovery(link);
q921_setstate(link, Q921_AWAITING_ESTABLISHMENT);
break;
}
}
}
break;
case Q921_TEI_ASSIGNED:
case Q921_AWAITING_ESTABLISHMENT:
case Q921_AWAITING_RELEASE:
/*
* Ignore this frame.
* We likely got reset and the other end has not realized it yet.
*/
break;
default:
pri_error(ctrl, "Don't know what to do with RNR in state %d(%s)\n",
link->state, q921_state2str(link->state));
break;
}
return res;
}
static void q921_acknowledge_pending_check(struct q921_link *link)
{
if (link->acknowledge_pending) {
link->acknowledge_pending = 0;
q921_rr(link, 0, 0);
}
}
static void q921_statemachine_check(struct q921_link *link)
{
switch (link->state) {
case Q921_MULTI_FRAME_ESTABLISHED:
q921_send_queued_iframes(link);
q921_acknowledge_pending_check(link);
break;
case Q921_TIMER_RECOVERY:
q921_acknowledge_pending_check(link);
break;
default:
break;
}
}
static pri_event *__q921_receive_qualified(struct q921_link *link, q921_h *h, int len)
{
int res;
pri_event *ev = NULL;
struct pri *ctrl;
ctrl = link->ctrl;
switch (h->h.data[0] & Q921_FRAMETYPE_MASK) {
case 0:
case 2:
ev = q921_iframe_rx(link, h, len);
break;
case 1:
switch ((h->s.x0 << 2) | h->s.ss) {
case 0x00:
ev = q921_rr_rx(link, h);
break;
case 0x01:
ev = q921_rnr_rx(link, h);
break;
case 0x02:
ev = q921_rej_rx(link, h);
break;
default:
pri_error(ctrl,
"!! XXX Unknown Supervisory frame x0=%d ss=%d, pf=%d, N(R)=%d, V(A)=%d, V(S)=%d XXX\n",
h->s.x0, h->s.ss, h->s.p_f, h->s.n_r, link->v_a, link->v_s);
break;
}
break;
case 3:
if (len < 3) {
pri_error(ctrl, "!! Received short unnumbered frame\n");
break;
}
switch ((h->u.m3 << 2) | h->u.m2) {
case 0x03:
ev = q921_dm_rx(link, h);
break;
case 0x00:
/* UI-frame */
if (ctrl->debug & PRI_DEBUG_Q931_DUMP) {
q931_dump(ctrl, h->h.tei, (q931_h *) h->u.data, len - 3, 0);
}
res = q931_receive(link, (q931_h *) h->u.data, len - 3);
if (res != -1 && (res & Q931_RES_HAVEEVENT)) {
ev = &ctrl->ev;
}
break;
case 0x08:
ev = q921_disc_rx(link, h);
break;
case 0x0F:
/* SABME */
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl, "TEI=%d Got SABME from %s peer.\n",
link->tei, h->h.c_r ? "network" : "cpe");
}
if (h->h.c_r) {
ctrl->remotetype = PRI_NETWORK;
if (ctrl->localtype == PRI_NETWORK) {
/* We can't both be networks */
ev = pri_mkerror(ctrl, "We think we're the network, but they think they're the network, too.");
break;
}
} else {
ctrl->remotetype = PRI_CPE;
if (ctrl->localtype == PRI_CPE) {
/* We can't both be CPE */
ev = pri_mkerror(ctrl, "We think we're the CPE, but they think they're the CPE too.\n");
break;
}
}
ev = q921_sabme_rx(link, h);
break;
case 0x0C:
ev = q921_ua_rx(link, h);
break;
case 0x11:
ev = q921_frmr_rx(link, h);
break;
case 0x17:
pri_error(ctrl, "!! XID frames not supported\n");
break;
default:
pri_error(ctrl, "!! Don't know what to do with u-frame (m3=%d, m2=%d)\n",
h->u.m3, h->u.m2);
break;
}
break;
}
q921_statemachine_check(link);
return ev;
}
static pri_event *q921_handle_unmatched_frame(struct pri *ctrl, q921_h *h, int len)
{
if (!BRI_NT_PTMP(ctrl)) {
return NULL;
}
if (h->h.tei < Q921_TEI_AUTO_FIRST) {
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl, "Manual TEI range is not supported in NT-PTMP mode. Discarding\n");
}
return NULL;
}
if (h->h.sapi != Q921_SAPI_CALL_CTRL) {
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl, "Message with SAPI other than CALL CTRL is discarded\n");
}
return NULL;
}
/* This means an unrecognized TEI that we'll kill */
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl,
"Could not find a layer 2 link for received frame with SAPI/TEI of %d/%d.\n",
h->h.sapi, h->h.tei);
pri_message(ctrl, "Sending TEI release, in order to re-establish TEI state\n");
}
q921_tei_remove(ctrl, h->h.tei);
return NULL;
}
/* This code assumes that the pri structure is the master pri */
static pri_event *__q921_receive(struct pri *ctrl, q921_h *h, int len)
{
pri_event *ev = NULL;
struct q921_link *link;
/* Discard FCS */
len -= 2;
if (ctrl->debug & (PRI_DEBUG_Q921_DUMP | PRI_DEBUG_Q921_RAW)) {
q921_dump(ctrl, h, len, ctrl->debug, 0);
}
/* Check some reject conditions -- Start by rejecting improper ea's */
if (h->h.ea1 || !h->h.ea2) {
return NULL;
}
if (h->h.sapi == Q921_SAPI_LAYER2_MANAGEMENT) {
return q921_mdl_receive(ctrl, &h->u, len);
}
if (h->h.tei == Q921_TEI_GROUP && h->h.sapi != Q921_SAPI_CALL_CTRL) {
pri_error(ctrl, "Do not handle group messages to services other than MDL or CALL CTRL\n");
return NULL;
}
if (BRI_TE_PTMP(ctrl)) {
/* We're operating on the specific TEI link */
link = ctrl->link.next;
if (h->h.sapi == link->sapi
&& ((link->state >= Q921_TEI_ASSIGNED
&& h->h.tei == link->tei)
|| h->h.tei == Q921_TEI_GROUP)) {
ev = __q921_receive_qualified(link, h, len);
}
/* Only support reception on our specific TEI link */
} else if (BRI_NT_PTMP(ctrl)) {
link = pri_find_tei(ctrl, h->h.sapi, h->h.tei);
if (link) {
ev = __q921_receive_qualified(link, h, len);
} else {
ev = q921_handle_unmatched_frame(ctrl, h, len);
}
} else if (PTP_MODE(ctrl)
&& h->h.sapi == ctrl->link.sapi
&& (h->h.tei == ctrl->link.tei || h->h.tei == Q921_TEI_GROUP)) {
ev = __q921_receive_qualified(&ctrl->link, h, len);
} else {
ev = NULL;
}
if (ctrl->debug & PRI_DEBUG_Q921_DUMP) {
pri_message(ctrl, "Done handling message for SAPI/TEI=%d/%d\n", h->h.sapi, h->h.tei);
}
return ev;
}
pri_event *q921_receive(struct pri *ctrl, q921_h *h, int len)
{
pri_event *e;
e = __q921_receive(ctrl, h, len);
ctrl->q921_rxcount++;
return e;
}
static void q921_establish_data_link(struct q921_link *link)
{
q921_clear_exception_conditions(link);
link->RC = 0;
stop_t203(link);
reschedule_t200(link);
q921_send_sabme(link);
}
static void nt_ptmp_dchannel_up(void *vpri)
{
struct pri *ctrl = vpri;
ctrl->schedev = 1;
ctrl->ev.gen.e = PRI_EVENT_DCHAN_UP;
}
void q921_start(struct q921_link *link)
{
struct pri *ctrl;
ctrl = link->ctrl;
if (PTMP_MODE(ctrl)) {
if (TE_MODE(ctrl)) {
q921_setstate(link, Q921_ASSIGN_AWAITING_TEI);
q921_tei_request(link);
} else {
q921_setstate(link, Q921_TEI_UNASSIGNED);
pri_schedule_event(ctrl, 0, nt_ptmp_dchannel_up, ctrl);
if (!ctrl->link.next) {
/*
* We do not have any TEI's so make sure there are no devices
* that think they have a TEI. A device may think it has a TEI
* if the upper layer program is restarted or the system
* reboots.
*/
q921_tei_remove(ctrl, Q921_TEI_GROUP);
}
}
} else {
/* PTP mode, no need for TEI management junk */
q921_establish_data_link(link);
link->l3_initiated = 1;
q921_setstate(link, Q921_AWAITING_ESTABLISHMENT);
}
}
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