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libpri/q921.c
Richard Mudgett d1cac6352a Fix I-frame retransmission quirks. 
Revamped the I-frame retransmission queue to better comply with Q.921:
Figure B.7/Q.921 (sheet 1 of 10) and Figure B.9/Q.921 (Sheet 5 of 5).  The
changes prevent retransmitting I-frames when the peer is busy (RNR) (Q.921
Section 5.6.5) and eliminate an unnecessary delay sending new I-frames
after an I-frame retransmission.

Related to JIRA LIBPRI-60


git-svn-id: https://origsvn.digium.com/svn/libpri/branches/1.4@2200 2fbb986a-6c06-0410-b554-c9c1f0a7f128
2011-02-14 23:33:56 +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(link, hf) do { \
memset(&(hf),0,sizeof(hf)); \
(hf).h.sapi = (link)->sapi; \
(hf).h.ea1 = 0; \
(hf).h.ea2 = 1; \
(hf).h.tei = (link)->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 & PRI_DEBUG_Q921_RAW, 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_send_tei(struct pri *ctrl, enum q921_tei_identity message, int ri, int ai, int iscommand)
{
q921_u *f;
struct q921_link *link;
link = &ctrl->link;
if (!(f = calloc(1, sizeof(*f) + 5)))
return;
Q921_INIT(link, *f);
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 TEI management 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);
++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_send_tei(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_send_tei(ctrl, Q921_TEI_IDENTITY_REMOVE, 0, tei, 1);
q921_send_tei(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_INIT(link, h);
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_INIT(link, h);
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_INIT(link, h);
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_INIT(link, h);
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");
}
}
static void restart_timer_expire(void *vlink)
{
struct q921_link *link = vlink;
struct pri *ctrl;
ctrl = link->ctrl;
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl, "SAPI/TEI=%d/%d Kick starting link\n", link->sapi, link->tei);
}
link->restart_timer = 0;
switch (link->state) {
case Q921_TEI_ASSIGNED:
/* Try to bring layer 2 up. */
q921_discard_iqueue(link);
q921_establish_data_link(link);
link->l3_initiated = 1;
q921_setstate(link, Q921_AWAITING_ESTABLISHMENT);
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;
}
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);
}
static pri_event *q921_ptp_delay_restart(struct q921_link *link)
{
pri_event *ev;
struct pri *ctrl;
ctrl = link->ctrl;
if (PTP_MODE(ctrl)) {
/*
* 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 PTP links.
*/
restart_timer_start(link);
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;
}
/* 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_INIT(link, h);
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_INIT(link, h);
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_ptp_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_ptp_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(link, f->h);
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 showraw, int txrx)
{
int x;
const char *type;
char direction_tag;
direction_tag = txrx ? '>' : '<';
pri_message(ctrl, "\n");
q921_dump_pri_by_h(ctrl, direction_tag, h);
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(ctrl, "%c [ %s]\n", direction_tag, buf);
free(buf);
}
}
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;
if (!ctrl->link.next) {
/* No TEI links remain. */
ctrl->t201_timer = 0;
return;
}
/* 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_send_tei(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 pri_event *q921_receive_MDL(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 (!BRI_NT_PTMP(ctrl) && !BRI_TE_PTMP(ctrl)) {
return pri_mkerror(ctrl,
"Received MDL/TEI managemement message, but configured for mode other than PTMP!\n");
}
if (ctrl->debug & PRI_DEBUG_Q921_STATE) {
pri_message(ctrl, "Received MDL message\n");
}
if (len <= &h->data[0] - (u_int8_t *) h) {
pri_error(ctrl, "Received short 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 %d(%s) with Ai E bit not set.\n", h->data[3],
q921_tei_mgmt2str(h->data[3]));
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)) {
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_send_tei(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_send_tei(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);
}
sub->next = pri_link_new(ctrl, Q921_SAPI_CALL_CTRL, tei);
if (!sub->next) {
pri_error(ctrl, "Unable to allocate layer 2 link for new TEI %d\n", tei);
return NULL;
}
q921_setstate(sub->next, Q921_TEI_ASSIGNED);
q921_send_tei(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);
}
break;
case Q921_TEI_IDENTITY_CHECK_RESPONSE:
if (!BRI_NT_PTMP(ctrl)) {
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)) {
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 (!BRI_TE_PTMP(ctrl)) {
return NULL;
}
/* Assuming 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 asking for one. */
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);
ctrl->ev.gen.e = PRI_EVENT_DCHAN_UP;
res = &ctrl->ev;
break;
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 (!BRI_TE_PTMP(ctrl)) {
return NULL;
}
/* Assuming 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_send_tei(ctrl, Q921_TEI_IDENTITY_CHECK_RESPONSE, random() % 65535, link->tei, 1);
}
break;
case Q921_TEI_IDENTITY_REMOVE:
if (!BRI_TE_PTMP(ctrl)) {
return NULL;
}
/* Assuming 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_ptp_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:
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_ptp_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_ptp_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_ptp_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 (h->h.tei < 64) {
pri_error(ctrl, "Do not support manual TEI range. Discarding\n");
return NULL;
}
if (h->h.sapi != Q921_SAPI_CALL_CTRL) {
pri_error(ctrl, "Message with SAPI other than CALL CTRL is discarded\n");
return NULL;
}
/* If we're NT-PTMP, this means an unrecognized TEI that we'll kill */
if (BRI_NT_PTMP(ctrl)) {
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 & PRI_DEBUG_Q921_RAW, 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_receive_MDL(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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