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libpri/q921.c

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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
*/
#define Q921_INIT(pri, hf) do { \
memset(&(hf),0,sizeof(hf)); \
(hf).h.sapi = (pri)->sapi; \
(hf).h.ea1 = 0; \
(hf).h.ea2 = 1; \
(hf).h.tei = (pri)->tei; \
} while(0)
static void reschedule_t200(struct pri *pri);
static void q921_dump_pri(struct pri *pri);
static void q921_establish_data_link(struct pri *pri);
static void q921_mdl_error(struct pri *pri, char error);
static void q921_mdl_remove(struct pri *pri);
static void q921_setstate(struct pri *pri, int newstate)
{
if (pri->debug & PRI_DEBUG_Q921_STATE) {
if ((pri->q921_state != newstate) && (newstate != 7) && (newstate != 8)) {
pri_message(pri, "Changing from state %d to %d\n", pri->q921_state, newstate);
}
}
pri->q921_state = newstate;
}
static void q921_discard_retransmissions(struct pri *pri)
{
struct q921_frame *f, *p;
f = pri->txqueue;
while(f) {
p = f;
f = f->next;
/* Free frame */
free(p);
}
pri->txqueue = NULL;
}
static void q921_discard_iqueue(struct pri *pri)
{
q921_discard_retransmissions(pri);
}
static int q921_transmit(struct pri *pri, q921_h *h, int len)
{
int res;
if (pri->master)
pri = pri->master;
#ifdef RANDOM_DROPS
if (!(random() % 3)) {
pri_message(pri, " === Dropping Packet ===\n");
return 0;
}
#endif
#ifdef LIBPRI_COUNTERS
pri->q921_txcount++;
#endif
/* Just send it raw */
if (pri->debug & (PRI_DEBUG_Q921_DUMP | PRI_DEBUG_Q921_RAW))
q921_dump(pri, h, len, pri->debug & PRI_DEBUG_Q921_RAW, 1);
/* Write an extra two bytes for the FCS */
res = pri->write_func ? pri->write_func(pri, h, len + 2) : 0;
if (res != (len + 2)) {
pri_error(pri, "Short write: %d/%d (%s)\n", res, len + 2, strerror(errno));
return -1;
}
return 0;
}
static void q921_send_tei(struct pri *pri, int message, int ri, int ai, int iscommand)
{
q921_u *f;
if (!(f = calloc(1, sizeof(*f) + 5)))
return;
Q921_INIT(pri, *f);
f->h.c_r = (pri->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 (pri->debug & PRI_DEBUG_Q921_STATE)
pri_message(pri, "Sending TEI management message %d, TEI=%d\n", message, ai);
q921_transmit(pri, (q921_h *)f, 8);
free(f);
}
static void q921_tei_request(void *vpri)
{
struct pri *pri = (struct pri *)vpri;
pri->n202_counter++;
if (pri->n202_counter > pri->timers[PRI_TIMER_N202]) {
pri_error(pri, "Unable to receive TEI from network!\n");
pri->n202_counter = 0;
return;
}
pri->ri = random() % 65535;
q921_send_tei(PRI_MASTER(pri), Q921_TEI_IDENTITY_REQUEST, pri->ri, Q921_TEI_GROUP, 1);
pri_schedule_del(pri, pri->t202_timer);
pri->t202_timer = pri_schedule_event(pri, pri->timers[PRI_TIMER_T202], q921_tei_request, pri);
}
static void q921_send_ua(struct pri *pri, int pfbit)
{
q921_h h;
Q921_INIT(pri, h);
h.u.m3 = 3; /* M3 = 3 */
h.u.m2 = 0; /* M2 = 0 */
h.u.p_f = pfbit; /* Final bit on */
h.u.ft = Q921_FRAMETYPE_U;
switch(pri->localtype) {
case PRI_NETWORK:
h.h.c_r = 0;
break;
case PRI_CPE:
h.h.c_r = 1;
break;
default:
pri_error(pri, "Don't know how to U/A on a type %d node\n", pri->localtype);
return;
}
if (pri->debug & (PRI_DEBUG_Q921_STATE | PRI_DEBUG_Q921_DUMP))
pri_message(pri, "Sending Unnumbered Acknowledgement\n");
q921_transmit(pri, &h, 3);
}
static void q921_send_sabme(struct pri *pri)
{
q921_h h;
Q921_INIT(pri, 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(pri->localtype) {
case PRI_NETWORK:
h.h.c_r = 1;
break;
case PRI_CPE:
h.h.c_r = 0;
break;
default:
pri_error(pri, "Don't know how to U/A on a type %d node\n", pri->localtype);
return;
}
q921_transmit(pri, &h, 3);
}
#if 0
static void q921_send_sabme_now(void *vpri)
{
q921_send_sabme(vpri, 1);
}
#endif
static int q921_ack_packet(struct pri *pri, int num)
{
struct q921_frame *f, *prev = NULL;
f = pri->txqueue;
while (f) {
if (f->h.n_s == num) {
/* Cancel each packet as necessary */
/* That's our packet */
if (prev)
prev->next = f->next;
else
pri->txqueue = f->next;
if (pri->debug & PRI_DEBUG_Q921_DUMP)
pri_message(pri, "-- ACKing packet %d, new txqueue is %d (-1 means empty)\n", f->h.n_s, pri->txqueue ? pri->txqueue->h.n_s : -1);
/* Update v_a */
free(f);
return 1;
}
prev = f;
f = f->next;
}
return 0;
}
static void t203_expire(void *);
static void t200_expire(void *);
static void reschedule_t200(struct pri *pri)
{
if (pri->debug & PRI_DEBUG_Q921_DUMP)
pri_message(pri, "-- Restarting T200 timer\n");
pri_schedule_del(pri, pri->t200_timer);
pri->t200_timer = pri_schedule_event(pri, pri->timers[PRI_TIMER_T200], t200_expire, pri);
}
#define restart_t200(pri) reschedule_t200((pri))
#if 0
static void reschedule_t203(struct pri *pri)
{
if (pri->debug & PRI_DEBUG_Q921_DUMP)
pri_message(pri, "-- Restarting T203 timer\n");
pri_schedule_del(pri, pri->t203_timer);
pri->t203_timer = pri_schedule_event(pri, pri->timers[PRI_TIMER_T203], t203_expire, pri);
}
#endif
#if 0
static int q921_unacked_iframes(struct pri *pri)
{
struct q921_frame *f = pri->txqueue;
int cnt = 0;
while(f) {
if (f->transmitted)
cnt++;
f = f->next;
}
return cnt;
}
#endif
static void start_t203(struct pri *pri)
{
if (pri->t203_timer) {
if (pri->debug & PRI_DEBUG_Q921_DUMP)
pri_message(pri, "T203 requested to start without stopping first\n");
pri_schedule_del(pri, pri->t203_timer);
}
if (pri->debug & PRI_DEBUG_Q921_DUMP)
pri_message(pri, "-- Starting T203 timer\n");
pri->t203_timer = pri_schedule_event(pri, pri->timers[PRI_TIMER_T203], t203_expire, pri);
}
static void stop_t203(struct pri *pri)
{
if (pri->t203_timer) {
if (pri->debug & PRI_DEBUG_Q921_DUMP)
pri_message(pri, "-- Stopping T203 timer\n");
pri_schedule_del(pri, pri->t203_timer);
pri->t203_timer = 0;
} else {
if (pri->debug & PRI_DEBUG_Q921_DUMP)
pri_message(pri, "-- T203 requested to stop when not started\n");
}
}
static void start_t200(struct pri *pri)
{
if (pri->t200_timer) {
if (pri->debug & PRI_DEBUG_Q921_DUMP)
pri_message(pri, "T200 requested to start without stopping first\n");
pri_schedule_del(pri, pri->t200_timer);
}
if (pri->debug & PRI_DEBUG_Q921_DUMP)
pri_message(pri, "-- Starting T200 timer\n");
pri->t200_timer = pri_schedule_event(pri, pri->timers[PRI_TIMER_T200], t200_expire, pri);
}
static void stop_t200(struct pri *pri)
{
if (pri->t200_timer) {
if (pri->debug & PRI_DEBUG_Q921_DUMP)
pri_message(pri, "-- Stopping T200 timer\n");
pri_schedule_del(pri, pri->t200_timer);
pri->t200_timer = 0;
} else {
if (pri->debug & PRI_DEBUG_Q921_DUMP)
pri_message(pri, "-- T200 requested to stop when not started\n");
}
}
/* 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 pri *pri)
{
struct q921_frame *f;
int frames_txd = 0;
if (pri->peer_rx_busy || (pri->v_s == Q921_ADD(pri->v_a, pri->k))) {
if (pri->debug & PRI_DEBUG_Q921_DUMP)
pri_message(pri, "Couldn't transmit I frame at this time due to peer busy condition or window shut\n");
return 0;
}
f = pri->txqueue;
while (f && (pri->v_s != Q921_ADD(pri->v_a, pri->k))) {
if (!f->transmitted) {
/* Send it now... */
if (pri->debug & PRI_DEBUG_Q921_DUMP)
pri_message(pri, "-- Finally transmitting %d, since window opened up (%d)\n", f->h.n_s, pri->k);
f->transmitted++;
f->h.n_s = pri->v_s;
f->h.n_r = pri->v_r;
f->h.ft = 0;
f->h.p_f = 0;
q921_transmit(pri, (q921_h *)(&f->h), f->len);
Q921_INC(pri->v_s);
frames_txd++;
pri->acknowledge_pending = 0;
}
f = f->next;
}
if (frames_txd) {
if (!pri->t200_timer) {
stop_t203(pri);
start_t200(pri);
}
}
return frames_txd;
}
static void q921_reject(struct pri *pri, int pf)
{
q921_h h;
Q921_INIT(pri, h);
h.s.x0 = 0; /* Always 0 */
h.s.ss = 2; /* Reject */
h.s.ft = 1; /* Frametype (01) */
h.s.n_r = pri->v_r; /* Where to start retransmission */
h.s.p_f = pf;
switch(pri->localtype) {
case PRI_NETWORK:
h.h.c_r = 0;
break;
case PRI_CPE:
h.h.c_r = 1;
break;
default:
pri_error(pri, "Don't know how to U/A on a type %d node\n", pri->localtype);
return;
}
if (pri->debug & PRI_DEBUG_Q921_DUMP)
pri_message(pri, "Sending Reject (%d)\n", pri->v_r);
q921_transmit(pri, &h, 4);
}
static void q921_rr(struct pri *pri, int pbit, int cmd) {
q921_h h;
Q921_INIT(pri, h);
h.s.x0 = 0; /* Always 0 */
h.s.ss = 0; /* Receive Ready */
h.s.ft = 1; /* Frametype (01) */
h.s.n_r = pri->v_r; /* N/R */
h.s.p_f = pbit; /* Poll/Final set appropriately */
switch(pri->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(pri, "Don't know how to U/A on a type %d node\n", pri->localtype);
return;
}
if (pri->debug & PRI_DEBUG_Q921_DUMP)
pri_message(pri, "Sending Receiver Ready (%d)\n", pri->v_r);
q921_transmit(pri, &h, 4);
}
static void transmit_enquiry(struct pri *pri)
{
if (!pri->own_rx_busy) {
q921_rr(pri, 1, 1);
pri->acknowledge_pending = 0;
start_t200(pri);
} else {
/* XXX: Implement me... */
}
}
static void t200_expire(void *vpri)
{
struct pri *pri = vpri;
if (pri->debug & PRI_DEBUG_Q921_DUMP) {
pri_message(pri, "%s\n", __FUNCTION__);
q921_dump_pri(pri);
}
pri->t200_timer = 0;
switch (pri->q921_state) {
case Q921_MULTI_FRAME_ESTABLISHED:
pri->RC = 0;
transmit_enquiry(pri);
pri->RC++;
q921_setstate(pri, Q921_TIMER_RECOVERY);
break;
case Q921_TIMER_RECOVERY:
/* SDL Flow Figure B.8/Q.921 Page 81 */
if (pri->RC != pri->timers[PRI_TIMER_N200]) {
#if 0
if (pri->v_s == pri->v_a) {
transmit_enquiry(pri);
}
#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(pri);
#endif
pri->RC++;
} else {
//pri_error(pri, "MDL-ERROR (I): T200 = N200 in timer recovery state\n");
q921_mdl_error(pri, 'I');
q921_establish_data_link(pri);
pri->l3initiated = 0;
q921_setstate(pri, Q921_AWAITING_ESTABLISHMENT);
}
break;
case Q921_AWAITING_ESTABLISHMENT:
if (pri->RC != pri->timers[PRI_TIMER_N200]) {
pri->RC++;
q921_send_sabme(pri);
start_t200(pri);
} else {
q921_discard_iqueue(pri);
//pri_error(pri, "MDL-ERROR (G) : T200 expired N200 times in state %d\n", pri->q921_state);
q921_mdl_error(pri, 'G');
q921_setstate(pri, Q921_TEI_ASSIGNED);
/* DL-RELEASE indication */
q931_dl_indication(pri, PRI_EVENT_DCHAN_DOWN);
}
break;
default:
pri_error(pri, "Cannot handle T200 expire in state %d\n", pri->q921_state);
}
}
/* This is sending a DL-UNIT-DATA request */
int q921_transmit_uiframe(struct pri *pri, void *buf, int len)
{
uint8_t ubuf[512];
q921_h *h = (void *)&ubuf[0];
if (len >= 512) {
pri_error(pri, "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 = pri->tei;
h->u.m3 = 0;
h->u.m2 = 0;
h->u.p_f = 0; /* Poll bit set */
h->u.ft = Q921_FRAMETYPE_U;
switch(pri->localtype) {
case PRI_NETWORK:
h->h.c_r = 1;
break;
case PRI_CPE:
h->h.c_r = 0;
break;
default:
pri_error(pri, "Don't know how to U/A on a type %d node\n", pri->localtype);
return -1;
}
memcpy(h->u.data, buf, len);
q921_transmit(pri, h, len + 3);
return 0;
}
static struct pri * pri_find_tei(struct pri *vpri, int sapi, int tei)
{
struct pri *pri;
for (pri = PRI_MASTER(vpri); pri; pri = pri->subchannel) {
if (pri->tei == tei && pri->sapi == sapi)
return pri;
}
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 pri *vpri, int tei, void *buf, int len, int cr)
{
q921_frame *f, *prev=NULL;
struct pri *pri;
if (BRI_NT_PTMP(vpri)) {
if (tei == Q921_TEI_GROUP) {
pri_error(vpri, "Huh?! For NT-PTMP, we shouldn't be sending I-frames out the group TEI\n");
return 0;
}
pri = pri_find_tei(vpri, Q921_SAPI_CALL_CTRL, tei);
if (!pri) {
pri_error(vpri, "Huh?! Unable to locate PRI associated with TEI %d. Did we have to ditch it due to error conditions?\n", tei);
return 0;
}
} else if (BRI_TE_PTMP(vpri)) {
/* We don't care what the tei is, since we only support one sub and one TEI */
pri = PRI_MASTER(vpri)->subchannel;
if (pri->q921_state == Q921_TEI_UNASSIGNED) {
q921_tei_request(pri);
q921_setstate(pri, Q921_ESTABLISH_AWAITING_TEI);
}
} else {
/* Should just be PTP modes, which shouldn't have subs */
pri = vpri;
}
/* Figure B.7/Q.921 Page 70 */
switch (pri->q921_state) {
case Q921_TEI_ASSIGNED:
/* If we aren't in a state compatiable with DL-DATA requests, start getting us there here */
q921_establish_data_link(pri);
pri->l3initiated = 1;
q921_setstate(pri, Q921_AWAITING_ESTABLISHMENT);
/* For all rest, we've done the work to get us up prior to this and fall through */
case Q921_TEI_UNASSIGNED:
case Q921_ESTABLISH_AWAITING_TEI:
case Q921_ASSIGN_AWAITING_TEI:
case Q921_TIMER_RECOVERY:
case Q921_AWAITING_ESTABLISHMENT:
case Q921_MULTI_FRAME_ESTABLISHED:
for (f=pri->txqueue; f; f = f->next) prev = f;
f = calloc(1, sizeof(q921_frame) + len + 2);
if (f) {
Q921_INIT(pri, f->h);
switch(pri->localtype) {
case PRI_NETWORK:
if (cr)
f->h.h.c_r = 1;
else
f->h.h.c_r = 0;
break;
case PRI_CPE:
if (cr)
f->h.h.c_r = 0;
else
f->h.h.c_r = 1;
break;
}
f->next = NULL;
f->transmitted = 0;
f->len = len + 4;
memcpy(f->h.data, buf, len);
if (prev)
prev->next = f;
else
pri->txqueue = f;
if (pri->q921_state != Q921_MULTI_FRAME_ESTABLISHED) {
return 0;
}
if (pri->peer_rx_busy || (pri->v_s == Q921_ADD(pri->v_a, pri->k))) {
if (pri->debug & PRI_DEBUG_Q921_DUMP)
pri_message(pri, "Couldn't transmit I frame at this time due to peer busy condition or window shut\n");
return 0;
}
q921_send_queued_iframes(pri);
return 0;
} else {
pri_error(pri, "!! Out of memory for Q.921 transmit\n");
return -1;
}
default:
pri_error(pri, "Cannot transmit frames in state %d\n", pri->q921_state);
}
return 0;
}
static void t203_expire(void *vpri)
{
struct pri *pri = vpri;
if (pri->debug & PRI_DEBUG_Q921_DUMP)
pri_message(pri, "%s\n", __FUNCTION__);
pri->t203_timer = 0;
switch (pri->q921_state) {
case Q921_MULTI_FRAME_ESTABLISHED:
transmit_enquiry(pri);
pri->RC = 0;
q921_setstate(pri, Q921_TIMER_RECOVERY);
break;
default:
if (pri->debug & PRI_DEBUG_Q921_DUMP)
pri_message(pri, "T203 counter expired in weird state %d\n", pri->q921_state);
pri->t203_timer = 0;
}
}
static void q921_dump_iqueue_info(struct pri *pri, int force)
{
struct q921_frame *f;
int pending = 0, unacked = 0;
unacked = pending = 0;
for (f = pri->txqueue; f && f->next; f = f->next) {
if (f->transmitted) {
unacked++;
} else {
pending++;
}
}
if (force)
pri_error(pri, "Number of pending packets %d, sent but unacked %d\n", pending, unacked);
return;
}
static void q921_dump_pri_by_h(struct pri *pri, q921_h *h);
void q921_dump(struct pri *pri, q921_h *h, int len, int showraw, int txrx)
{
int x;
char *type;
char direction_tag;
q921_dump_pri_by_h(pri, h);
direction_tag = txrx ? '>' : '<';
if (showraw) {
char *buf = malloc(len * 3 + 1);
int buflen = 0;
if (buf) {
pri_message(pri, "\n");
for (x=0;x<len;x++)
buflen += sprintf(buf + buflen, "%02x ", h->raw[x]);
pri_message(pri, "%c [ %s]\n", direction_tag, buf);
free(buf);
}
}
pri_message(pri, "\n");
switch (h->h.data[0] & Q921_FRAMETYPE_MASK) {
case 0:
case 2:
pri_message(pri, "%c Informational frame:\n", direction_tag);
break;
case 1:
pri_message(pri, "%c Supervisory frame:\n", direction_tag);
break;
case 3:
pri_message(pri, "%c Unnumbered frame:\n", direction_tag);
break;
}
pri_message(pri, "%c SAPI: %02d C/R: %d EA: %d\n",
direction_tag,
h->h.sapi,
h->h.c_r,
h->h.ea1);
pri_message(pri, "%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(pri, "%c N(S): %03d 0: %d\n",
direction_tag,
h->i.n_s,
h->i.ft);
pri_message(pri, "%c N(R): %03d P: %d\n",
direction_tag,
h->i.n_r,
h->i.p_f);
pri_message(pri, "%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(pri, "%c Zero: %d S: %d 01: %d [ %s ]\n",
direction_tag,
h->s.x0,
h->s.ss,
h->s.ft,
type);
pri_message(pri, "%c N(R): %03d P/F: %d\n",
direction_tag,
h->s.n_r,
h->s.p_f);
pri_message(pri, "%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;
}
}
pri_message(pri, "%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(pri, "%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;
int tei;
ri = (h->u.data[1] << 8) | h->u.data[2];
tei = (h->u.data[4] >> 1);
/* TEI assignment related */
switch (h->u.data[3]) {
case Q921_TEI_IDENTITY_REQUEST:
type = "TEI Identity Request";
break;
case Q921_TEI_IDENTITY_ASSIGNED:
type = "TEI Identity Assigned";
break;
case Q921_TEI_IDENTITY_CHECK_REQUEST:
type = "TEI Identity Check Request";
break;
case Q921_TEI_IDENTITY_REMOVE:
type = "TEI Identity Remove";
break;
case Q921_TEI_IDENTITY_DENIED:
type = "TEI Identity Denied";
break;
case Q921_TEI_IDENTITY_CHECK_RESPONSE:
type = "TEI Identity Check Response";
break;
case Q921_TEI_IDENTITY_VERIFY:
type = "TEI Identity Verify";
break;
default:
type = "Unknown";
break;
}
pri_message(pri, "%c MDL Message: %s (%d)\n", direction_tag, type, h->u.data[3]);
pri_message(pri, "%c RI: %d\n", direction_tag, ri);
pri_message(pri, "%c Ai: %d E:%d\n", direction_tag, (h->u.data[4] >> 1) & 0x7f, h->u.data[4] & 1);
}
}
static void q921_dump_pri(struct pri *pri)
{
pri_message(pri, "TEI: %d State %d\n", pri->tei, pri->q921_state);
pri_message(pri, "V(S) %d V(A) %d V(R) %d\n", pri->v_s, pri->v_a, pri->v_r);
pri_message(pri, "K %d, RC %d, l3initiated %d, reject_except %d ack_pend %d\n", pri->k, pri->RC, pri->l3initiated, pri->reject_exception, pri->acknowledge_pending);
pri_message(pri, "T200 %d, N200 %d, T203 %d\n", pri->t200_timer, 3, pri->t203_timer);
}
static void q921_dump_pri_by_h(struct pri *vpri, q921_h *h)
{
struct pri *pri = NULL;
if (BRI_NT_PTMP(vpri)) {
pri = pri_find_tei(vpri, h->h.sapi, h->h.tei);
} else if (BRI_TE_PTMP(vpri)) {
pri = PRI_MASTER(vpri)->subchannel;
} else
pri = vpri;
if (pri) {
q921_dump_pri(pri);
} else if (!PTMP_MODE(vpri)) {
pri_error(vpri, "Huh.... no pri found to dump\n");
}
}
static pri_event *q921_receive_MDL(struct pri *pri, q921_u *h, int len)
{
int ri;
struct pri *sub = pri;
pri_event *res = NULL;
int tei;
if (!BRI_NT_PTMP(pri) && !BRI_TE_PTMP(pri)) {
pri_error(pri, "Received MDL/TEI managemement message, but configured for mode other than PTMP!\n");
return NULL;
}
if (pri->debug & PRI_DEBUG_Q921_STATE)
pri_message(pri, "Received MDL message\n");
if (h->data[0] != 0x0f) {
pri_error(pri, "Received MDL with unsupported management entity %02x\n", h->data[0]);
return NULL;
}
if (!(h->data[4] & 0x01)) {
pri_error(pri, "Received MDL with multibyte TEI identifier\n");
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(pri)) {
return NULL;
}
if (tei != 127) {
pri_error(pri, "Received TEI identity request with invalid TEI %d\n", tei);
q921_send_tei(pri, Q921_TEI_IDENTITY_DENIED, ri, tei, 1);
}
tei = 64;
while (sub->subchannel) {
if (sub->subchannel->tei == tei)
++tei;
sub = sub->subchannel;
}
if (tei >= Q921_TEI_GROUP) {
pri_error(pri, "Reached maximum TEI quota, cannot assign new TEI\n");
return NULL;
}
sub->subchannel = __pri_new_tei(-1, pri->localtype, pri->switchtype, pri, NULL, NULL, NULL, tei, 1);
if (!sub->subchannel) {
pri_error(pri, "Unable to allocate D-channel for new TEI %d\n", tei);
return NULL;
}
q921_setstate(sub->subchannel, Q921_TEI_ASSIGNED);
if (pri->debug & PRI_DEBUG_Q921_STATE) {
pri_message(pri, "Allocating new TEI %d\n", tei);
}
q921_send_tei(pri, Q921_TEI_IDENTITY_ASSIGNED, ri, tei, 1);
break;
case Q921_TEI_IDENTITY_ASSIGNED:
if (!BRI_TE_PTMP(pri))
return NULL;
/* Assuming we're operating on the sub here */
pri = pri->subchannel;
switch (pri->q921_state) {
case Q921_ASSIGN_AWAITING_TEI:
case Q921_ESTABLISH_AWAITING_TEI:
break;
default:
pri_message(pri, "Ignoring unrequested TEI assign message\n");
return NULL;
}
if (ri != pri->ri) {
pri_message(pri, "TEI assignment received for invalid Ri %02x (our is %02x)\n", ri, pri->ri);
return NULL;
}
pri_schedule_del(pri, pri->t202_timer);
pri->t202_timer = 0;
pri->tei = tei;
switch (pri->q921_state) {
case Q921_ASSIGN_AWAITING_TEI:
q921_setstate(pri, Q921_TEI_ASSIGNED);
pri->ev.gen.e = PRI_EVENT_DCHAN_UP;
res = &pri->ev;
break;
case Q921_ESTABLISH_AWAITING_TEI:
q921_establish_data_link(pri);
pri->l3initiated = 1;
q921_setstate(pri, Q921_AWAITING_ESTABLISHMENT);
break;
default:
pri_error(pri, "Error 3\n");
return NULL;
}
break;
case Q921_TEI_IDENTITY_CHECK_REQUEST:
if (!BRI_TE_PTMP(pri))
return NULL;
if (pri->subchannel->q921_state < Q921_TEI_ASSIGNED)
return NULL;
/* If it's addressed to the group TEI or to our TEI specifically, we respond */
if ((tei == Q921_TEI_GROUP) || (tei == pri->subchannel->tei))
q921_send_tei(pri, Q921_TEI_IDENTITY_CHECK_RESPONSE, random() % 65535, pri->subchannel->tei, 1);
break;
case Q921_TEI_IDENTITY_REMOVE:
if (!BRI_TE_PTMP(pri))
return NULL;
if ((tei == Q921_TEI_GROUP) || (tei == pri->subchannel->tei)) {
q921_setstate(pri->subchannel, Q921_TEI_UNASSIGNED);
q921_start(pri->subchannel);
}
}
return res; /* Do we need to return something??? */
}
static int is_command(struct pri *pri, q921_h *h)
{
int command = 0;
int c_r = h->s.h.c_r;
if ((pri->localtype == PRI_NETWORK && c_r == 0) ||
(pri->localtype == PRI_CPE && c_r == 1))
command = 1;
return command;
}
static void q921_clear_exception_conditions(struct pri *pri)
{
pri->own_rx_busy = 0;
pri->peer_rx_busy = 0;
pri->reject_exception = 0;
pri->acknowledge_pending = 0;
}
static pri_event * q921_sabme_rx(struct pri *pri, q921_h *h)
{
pri_event *res = NULL;
switch (pri->q921_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(pri, h->u.p_f);
q921_clear_exception_conditions(pri);
//pri_error(pri, "MDL-ERROR (F), SABME in state %d\n", pri->q921_state);
q921_mdl_error(pri, 'F');
if (pri->v_s != pri->v_a) {
q921_discard_iqueue(pri);
/* DL-ESTABLISH indication */
q931_dl_indication(pri, PRI_EVENT_DCHAN_UP);
}
stop_t200(pri);
start_t203(pri);
pri->v_s = pri->v_a = pri->v_r = 0;
q921_setstate(pri, Q921_MULTI_FRAME_ESTABLISHED);
break;
case Q921_TEI_ASSIGNED:
q921_send_ua(pri, h->u.p_f);
q921_clear_exception_conditions(pri);
pri->v_s = pri->v_a = pri->v_r = 0;
/* DL-ESTABLISH indication */
q931_dl_indication(pri, PRI_EVENT_DCHAN_UP);
if (PTP_MODE(pri)) {
pri->ev.gen.e = PRI_EVENT_DCHAN_UP;
res = &pri->ev;
}
start_t203(pri);
q921_setstate(pri, Q921_MULTI_FRAME_ESTABLISHED);
break;
case Q921_AWAITING_ESTABLISHMENT:
q921_send_ua(pri, h->u.p_f);
break;
case Q921_AWAITING_RELEASE:
default:
pri_error(pri, "Cannot handle SABME in state %d\n", pri->q921_state);
}
return res;
}
static pri_event *q921_disc_rx(struct pri *pri, q921_h *h)
{
pri_event * res = NULL;
switch (pri->q921_state) {
case Q921_AWAITING_RELEASE:
q921_send_ua(pri, h->u.p_f);
break;
case Q921_MULTI_FRAME_ESTABLISHED:
case Q921_TIMER_RECOVERY:
q921_discard_iqueue(pri);
q921_send_ua(pri, h->u.p_f);
/* DL-RELEASE Indication */
q931_dl_indication(pri, PRI_EVENT_DCHAN_DOWN);
stop_t200(pri);
if (pri->q921_state == Q921_MULTI_FRAME_ESTABLISHED)
stop_t203(pri);
q921_setstate(pri, Q921_TEI_ASSIGNED);
break;
default:
pri_error(pri, "Don't know what to do with DISC in state %d\n", pri->q921_state);
break;
}
return res;
}
static void q921_mdl_remove(struct pri *pri)
{
switch (pri->q921_state) {
case Q921_TEI_ASSIGNED:
/* XXX: deviation! Since we don't have a UI queue, we just discard our I-queue */
q921_discard_iqueue(pri);
q921_setstate(pri, Q921_TEI_UNASSIGNED);
break;
case Q921_AWAITING_ESTABLISHMENT:
q921_discard_iqueue(pri);
/* DL-RELEASE indication */
q931_dl_indication(pri, PRI_EVENT_DCHAN_DOWN);
stop_t200(pri);
q921_setstate(pri, Q921_TEI_UNASSIGNED);
break;
case Q921_AWAITING_RELEASE:
q921_discard_iqueue(pri);
/* DL-RELEASE confirm */
stop_t200(pri);
break;
case Q921_MULTI_FRAME_ESTABLISHED:
q921_discard_iqueue(pri);
/* DL-RELEASE indication */
q931_dl_indication(pri, PRI_EVENT_DCHAN_DOWN);
stop_t200(pri);
stop_t203(pri);
q921_setstate(pri, Q921_TEI_UNASSIGNED);
break;
case Q921_TIMER_RECOVERY:
q921_discard_iqueue(pri);
/* DL-RELEASE indication */
q931_dl_indication(pri, PRI_EVENT_DCHAN_DOWN);
stop_t200(pri);
q921_setstate(pri, Q921_TEI_UNASSIGNED);
default:
pri_error(pri, "Cannot handle MDL remove when PRI is in state %d\n", pri->q921_state);
break;
}
if (BRI_NT_PTMP(pri) && pri->q921_state == Q921_TEI_UNASSIGNED) {
if (pri == PRI_MASTER(pri)) {
pri_error(pri, "Bad bad bad! Asked to free master\n");
return;
}
pri->mdl_free_me = 1;
}
}
static int q921_mdl_handle_network_error(struct pri *pri, char error)
{
int handled = 0;
switch (error) {
case 'C':
case 'D':
case 'G':
case 'H':
q921_mdl_remove(pri);
handled = 1;
break;
case 'A':
case 'B':
case 'E':
case 'F':
case 'I':
default:
pri_error(pri, "Network MDL can't handle error of type %c\n", error);
break;
}
return handled;
}
static int q921_mdl_handle_cpe_error(struct pri *pri, char error)
{
int handled = 0;
switch (error) {
case 'C':
case 'D':
case 'G':
case 'H':
q921_mdl_remove(pri);
handled = 1;
break;
case 'A':
case 'B':
case 'E':
case 'F':
case 'I':
break;
default:
pri_error(pri, "CPE MDL can't handle error of type %c\n", error);
break;
}
return handled;
}
static int q921_mdl_handle_ptp_error(struct pri *pri, char error)
{
int handled = 0;
/* 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 point to point links */
switch (error) {
case 'G':
/* We pick it back up and put it back together for this case */
q921_discard_iqueue(pri);
q921_establish_data_link(pri);
q921_setstate(pri, Q921_AWAITING_ESTABLISHMENT);
pri->l3initiated = 1;
pri->schedev = 1;
pri->ev.gen.e = PRI_EVENT_DCHAN_DOWN;
handled = 1;
break;
default:
pri_error(pri, "PTP MDL can't handle error of type %c\n", error);
}
return handled;
}
static void q921_mdl_handle_error(struct pri *pri, char error, int errored_state)
{
int handled = 0;
if (PTP_MODE(pri)) {
handled = q921_mdl_handle_ptp_error(pri, error);
} else {
if (pri->localtype == PRI_NETWORK) {
handled = q921_mdl_handle_network_error(pri, error);
} else {
handled = q921_mdl_handle_cpe_error(pri, error);
}
}
if (handled)
return;
switch (error) {
case 'C':
pri_error(pri, "MDL-ERROR (C): UA in state %d\n", errored_state);
break;
case 'D':
pri_error(pri, "MDL-ERROR (D): UA in state %d\n", errored_state);
break;
case 'A':
pri_error(pri, "MDL-ERROR (A): Got supervisory frame with p_f bit set to 1 in state %d\n", errored_state);
break;
case 'I':
pri_error(pri, "MDL-ERROR (I): T200 = N200 in timer recovery state %d\n", errored_state);
break;
case 'G':
pri_error(pri, "MDL-ERROR (G) : T200 expired N200 times in state %d\n", errored_state);
break;
case 'F':
pri_error(pri, "MDL-ERROR (F), SABME in state %d\n", errored_state);
break;
case 'H':
case 'B':
case 'E':
case 'J':
default:
pri_error(pri, "MDL-ERROR (%c) in state %d\n", error, errored_state);
}
return;
}
static void q921_mdl_handle_error_callback(void *vpri)
{
struct pri *pri = vpri;
q921_mdl_handle_error(pri, pri->mdl_error, pri->mdl_error_state);
pri->mdl_error = 0;
pri->mdl_timer = 0;
if (pri->mdl_free_me) {
struct pri *master = PRI_MASTER(pri);
struct pri *freep = NULL, *prev, *cur;
prev = master;
cur = master->subchannel;
while (cur) {
if (cur == pri) {
prev->subchannel = cur->subchannel;
freep = cur;
break;
}
prev = cur;
cur = cur->subchannel;
}
if (freep == NULL) {
pri_error(pri, "Huh!? no match found in list for TEI %d\n", pri->tei);
return;
}
if (pri->debug & PRI_DEBUG_Q921_STATE) {
pri_message(pri, "Freeing TEI of %d\n", freep->tei);
}
__pri_free_tei(freep);
}
return;
}
static void q921_mdl_error(struct pri *pri, char error)
{
if (pri->mdl_error) {
pri_error(pri, "Trying to queue an MDL error when one is already scheduled\n");
return;
}
pri->mdl_error = error;
pri->mdl_error_state = pri->q921_state;
pri->mdl_timer = pri_schedule_event(pri, 0, q921_mdl_handle_error_callback, pri);
}
static pri_event *q921_ua_rx(struct pri *pri, q921_h *h)
{
pri_event * res = NULL;
switch (pri->q921_state) {
case Q921_TEI_ASSIGNED:
//pri_error(pri, "MDL-ERROR (C, D): UA received in state %d\n", pri->q921_state);
if (h->u.p_f)
q921_mdl_error(pri, 'C');
else
q921_mdl_error(pri, 'D');
break;
case Q921_AWAITING_ESTABLISHMENT:
if (!h->u.p_f) {
pri_error(pri, "MDL-ERROR: Received UA with F = 0 while awaiting establishment\n");
break;
}
if (!pri->l3initiated) {
if (pri->v_s != pri->v_a) {
q921_discard_iqueue(pri);
/* return DL-ESTABLISH-INDICATION */
q931_dl_indication(pri, PRI_EVENT_DCHAN_UP);
}
} else {
/* Might not want this... */
pri->l3initiated = 0;
/* But do want this */
pri->v_r = 0;
/* return DL-ESTABLISH-CONFIRM */
}
if (PTP_MODE(pri)) {
pri->ev.gen.e = PRI_EVENT_DCHAN_UP;
res = &pri->ev;
}
stop_t200(pri);
start_t203(pri);
pri->v_s = pri->v_a = 0;
q921_setstate(pri, Q921_MULTI_FRAME_ESTABLISHED);
break;
case Q921_AWAITING_RELEASE:
if (!h->u.p_f) {
//pri_error(pri, "MDL-ERROR (D): UA in state %d w with P_F bit 0\n", pri->q921_state);
q921_mdl_error(pri, 'D');
} else {
/* return DL-RELEASE-CONFIRM */
stop_t200(pri);
q921_setstate(pri, Q921_TEI_ASSIGNED);
}
break;
case Q921_MULTI_FRAME_ESTABLISHED:
case Q921_TIMER_RECOVERY:
//pri_error(pri, "MDL-ERROR (C, D) UA in state %d\n", pri->q921_state);
q921_mdl_error(pri, 'C');
break;
default:
pri_error(pri, "Don't know what to do with UA in state %d\n", pri->q921_state);
break;
}
return res;
}
static void q921_enquiry_response(struct pri *pri)
{
if (pri->own_rx_busy) {
/* XXX : TODO later sometime */
pri_error(pri, "Implement me %s: own_rx_busy\n", __FUNCTION__);
//q921_rnr(pri);
} else {
q921_rr(pri, 1, 0);
}
pri->acknowledge_pending = 0;
}
static void n_r_error_recovery(struct pri *pri)
{
q921_mdl_error(pri, 'J');
q921_establish_data_link(pri);
pri->l3initiated = 0;
}
static void update_v_a(struct pri *pri, int n_r)
{
int idealcnt = 0, realcnt = 0;
int x;
/* Cancel each packet as necessary */
if (pri->debug & PRI_DEBUG_Q921_DUMP)
pri_message(pri, "-- ACKing all packets from %d to (but not including) %d\n", pri->v_a, n_r);
for (x = pri->v_a; x != n_r; Q921_INC(x)) {
idealcnt++;
realcnt += q921_ack_packet(pri, x);
}
if (idealcnt != realcnt) {
pri_error(pri, "Ideally should have ack'd %d frames, but actually ack'd %d. This is not good.\n", idealcnt, realcnt);
q921_dump_iqueue_info(pri, 1);
} else {
q921_dump_iqueue_info(pri, 0);
}
pri->v_a = n_r;
}
static int n_r_is_valid(struct pri *pri, int n_r)
{
int x;
for (x=pri->v_a; (x != pri->v_s) && (x != n_r); Q921_INC(x));
if (x != n_r) {
pri_error(pri, "N(R) %d not within ack window! Bad Bad Bad!\n", n_r);
return 0;
} else {
return 1;
}
}
static int q921_invoke_retransmission(struct pri *pri, int n_r);
static pri_event * timer_recovery_rr_rej_rx(struct pri *pri, q921_h *h)
{
/* Figure B.7/Q.921 Page 74 */
pri->peer_rx_busy = 0;
if (is_command(pri, h)) {
if (h->s.p_f) {
/* Enquiry response */
q921_enquiry_response(pri);
}
if (n_r_is_valid(pri, h->s.n_r)) {
update_v_a(pri, h->s.n_r);
} else {
goto n_r_error_out;
}
} else {
if (!h->s.p_f) {
if (n_r_is_valid(pri, h->s.n_r)) {
update_v_a(pri, h->s.n_r);
} else {
goto n_r_error_out;
}
} else {
if (n_r_is_valid(pri, h->s.n_r)) {
update_v_a(pri, h->s.n_r);
stop_t200(pri);
start_t203(pri);
q921_invoke_retransmission(pri, h->s.n_r);
q921_setstate(pri, Q921_MULTI_FRAME_ESTABLISHED);
} else {
goto n_r_error_out;
}
}
}
return NULL;
n_r_error_out:
n_r_error_recovery(pri);
q921_setstate(pri, Q921_AWAITING_ESTABLISHMENT);
return NULL;
}
static pri_event *q921_rr_rx(struct pri *pri, q921_h *h)
{
pri_event * res = NULL;
switch (pri->q921_state) {
case Q921_TIMER_RECOVERY:
res = timer_recovery_rr_rej_rx(pri, h);
break;
case Q921_MULTI_FRAME_ESTABLISHED:
/* Figure B.7/Q.921 Page 74 */
pri->peer_rx_busy = 0;
if (is_command(pri, h)) {
if (h->s.p_f) {
/* Enquiry response */
q921_enquiry_response(pri);
}
} else {
if (h->s.p_f) {
//pri_message(pri, "MDL-ERROR (A): Got RR response with p_f bit set to 1 in state %d\n", pri->q921_state);
q921_mdl_error(pri, 'A');
}
}
if (!n_r_is_valid(pri, h->s.n_r)) {
n_r_error_recovery(pri);
q921_setstate(pri, Q921_AWAITING_ESTABLISHMENT);
} else {
if (h->s.n_r == pri->v_s) {
update_v_a(pri, h->s.n_r);
stop_t200(pri);
start_t203(pri);
} else {
if (h->s.n_r != pri->v_a) {
/* Need to check the validity of n_r as well.. */
update_v_a(pri, h->s.n_r);
restart_t200(pri);
}
}
}
break;
default:
pri_error(pri, "Don't know what to do with RR in state %d\n", pri->q921_state);
break;
}
return res;
}
/* TODO: Look at this code more... */
static int q921_invoke_retransmission(struct pri *pri, int n_r)
{
int frames_txd = 0;
int frames_supposed_to_tx = 0;
q921_frame *f;
unsigned int local_v_s = pri->v_s;
for (f = pri->txqueue; f && (f->h.n_s != n_r); f = f->next);
while (f) {
if (f->transmitted) {
if (pri->debug & PRI_DEBUG_Q921_STATE)
pri_error(pri, "!! Got reject for frame %d, retransmitting frame %d now, updating n_r!\n", n_r, f->h.n_s);
f->h.n_r = pri->v_r;
f->h.p_f = 0;
q921_transmit(pri, (q921_h *)(&f->h), f->len);
frames_txd++;
}
f = f->next;
}
while (local_v_s != n_r) {
Q921_DEC(local_v_s);
frames_supposed_to_tx++;
}
if (frames_supposed_to_tx != frames_txd) {
pri_error(pri, "!!!!!!!!!!!! Should have only transmitted %d frames!\n", frames_supposed_to_tx);
}
return frames_txd;
}
static pri_event *q921_rej_rx(struct pri *pri, q921_h *h)
{
pri_event * res = NULL;
if (pri->debug & PRI_DEBUG_Q921_STATE) {
pri_message(pri, "!! Got reject for frame %d in state %d\n", h->s.n_r, pri->q921_state);
}
switch (pri->q921_state) {
case Q921_TIMER_RECOVERY:
res = timer_recovery_rr_rej_rx(pri, h);
break;
case Q921_MULTI_FRAME_ESTABLISHED:
/* Figure B.7/Q.921 Page 74 */
pri->peer_rx_busy = 0;
if (is_command(pri, h)) {
if (h->s.p_f) {
/* Enquiry response */
q921_enquiry_response(pri);
}
} else {
if (h->s.p_f) {
//pri_message(pri, "MDL-ERROR (A): Got REJ response with p_f bit set to 1 in state %d\n", pri->q921_state);
q921_mdl_error(pri, 'A');
}
}
if (!n_r_is_valid(pri, h->s.n_r)) {
n_r_error_recovery(pri);
q921_setstate(pri, Q921_AWAITING_ESTABLISHMENT);
} else {
update_v_a(pri, h->s.n_r);
stop_t200(pri);
start_t203(pri);
q921_invoke_retransmission(pri, h->s.n_r);
}
return NULL;
default:
pri_error(pri, "Don't know what to do with RR in state %d\n", pri->q921_state);
return NULL;
}
return res;
}
static pri_event *q921_iframe_rx(struct pri *pri, q921_h *h, int len)
{
pri_event * eres = NULL;
int res = 0;
switch (pri->q921_state) {
case Q921_TIMER_RECOVERY:
case Q921_MULTI_FRAME_ESTABLISHED:
/* FIXME: Verify that it's a command ... */
if (pri->own_rx_busy) {
/* XXX: Note: There's a difference in th P/F between both states */
/* DEVIATION: Handle own rx busy */
}
if (h->i.n_s == pri->v_r) {
Q921_INC(pri->v_r);
pri->reject_exception = 0;
//res = q931_receive(PRI_MASTER(pri), pri->tei, (q931_h *)h->i.data, len - 4);
res = q931_receive(pri, pri->tei, (q931_h *)h->i.data, len - 4);
if (res != -1 && (res & Q931_RES_HAVEEVENT)) {
eres = &pri->ev;
}
if (h->i.p_f) {
q921_rr(pri, 1, 0);
pri->acknowledge_pending = 0;
} else {
if (!pri->acknowledge_pending) {
/* XXX: Fix acknowledge_pending */
pri->acknowledge_pending = 1;
}
}
} else {
if (pri->reject_exception) {
if (h->i.p_f) {
q921_rr(pri, 1, 0);
pri->acknowledge_pending = 0;
}
} else {
pri->reject_exception = 1;
q921_reject(pri, h->i.p_f);
pri->acknowledge_pending = 0;
}
}
if (!n_r_is_valid(pri, h->i.n_r)) {
n_r_error_recovery(pri);
q921_setstate(pri, Q921_AWAITING_ESTABLISHMENT);
} else {
if (pri->q921_state == Q921_TIMER_RECOVERY) {
update_v_a(pri, h->i.n_r);
} else {
if (pri->peer_rx_busy) {
update_v_a(pri, h->i.n_r);
} else {
if (h->i.n_r == pri->v_s) {
update_v_a(pri, h->i.n_r);
stop_t200(pri);
start_t203(pri);
} else {
if (h->i.n_r != pri->v_a) {
update_v_a(pri, h->i.n_r);
stop_t200(pri);
start_t200(pri);
}
}
}
}
}
break;
default:
pri_error(pri, "Don't know what to do with an I frame in state %d\n", pri->q921_state);
break;
}
return eres;
}
static pri_event *q921_dm_rx(struct pri *pri, q921_h *h)
{
pri_event * res = NULL;
switch (pri->q921_state) {
case Q921_TEI_ASSIGNED:
if (h->u.p_f)
break;
/* else */
q921_establish_data_link(pri);
pri->l3initiated = 1;
q921_setstate(pri, Q921_AWAITING_ESTABLISHMENT);
break;
case Q921_AWAITING_ESTABLISHMENT:
if (!h->u.p_f)
break;
q921_discard_iqueue(pri);
/* DL-RELEASE indication */
q931_dl_indication(pri, PRI_EVENT_DCHAN_DOWN);
stop_t200(pri);
q921_setstate(pri, Q921_TEI_ASSIGNED);
break;
case Q921_AWAITING_RELEASE:
if (!h->u.p_f)
break;
/* DL-RELEASE confirm */
stop_t200(pri);
q921_setstate(pri, Q921_TEI_ASSIGNED);
break;
case Q921_MULTI_FRAME_ESTABLISHED:
if (h->u.p_f) {
/* MDL-ERROR (B) indication */
q921_mdl_error(pri, 'B');
break;
}
q921_mdl_error(pri, 'E');
q921_establish_data_link(pri);
pri->l3initiated = 0;
q921_setstate(pri, Q921_AWAITING_ESTABLISHMENT);
break;
case Q921_TIMER_RECOVERY:
if (h->u.p_f) {
/* MDL-ERROR (B) indication */
q921_mdl_error(pri, 'B');
} else {
/* MDL-ERROR (E) indication */
q921_mdl_error(pri, 'E');
}
q921_establish_data_link(pri);
pri->l3initiated = 0;
q921_setstate(pri, Q921_AWAITING_ESTABLISHMENT);
break;
default:
pri_error(pri, "Don't know what to do with DM frame in state %d\n", pri->q921_state);
break;
}
return res;
}
static pri_event *q921_rnr_rx(struct pri *pri, q921_h *h)
{
pri_event * res = NULL;
switch (pri->q921_state) {
case Q921_MULTI_FRAME_ESTABLISHED:
pri->peer_rx_busy = 1;
if (!is_command(pri, h)) {
if (h->s.p_f) {
/* MDL-ERROR (A) indication */
q921_mdl_error(pri, 'A');
}
} else {
if (h->s.p_f) {
q921_enquiry_response(pri);
}
}
if (!n_r_is_valid(pri, h->s.n_r)) {
n_r_error_recovery(pri);
q921_setstate(pri, Q921_AWAITING_ESTABLISHMENT);
} else {
update_v_a(pri, h->s.n_r);
stop_t203(pri);
restart_t200(pri);
}
break;
case Q921_TIMER_RECOVERY:
pri->peer_rx_busy = 1;
if (is_command(pri, h)) {
if (h->s.p_f) {
q921_enquiry_response(pri);
if (n_r_is_valid(pri, h->s.n_r)) {
update_v_a(pri, h->s.n_r);
break;
} else {
n_r_error_recovery(pri);
q921_setstate(pri, Q921_AWAITING_ESTABLISHMENT);
break;
}
}
} else {
if (h->s.p_f) {
if (n_r_is_valid(pri, h->s.n_r)) {
update_v_a(pri, h->s.n_r);
restart_t200(pri);
q921_invoke_retransmission(pri, h->s.n_r);
q921_setstate(pri, Q921_MULTI_FRAME_ESTABLISHED);
break;
} else {
n_r_error_recovery(pri);
q921_setstate(pri, Q921_AWAITING_ESTABLISHMENT);
break;
}
}
}
break;
default:
pri_error(pri, "Don't know what to do with RNR in state %d\n", pri->q921_state);
break;
}
return res;
}
static void q921_acknowledge_pending_check(struct pri *pri)
{
if (pri->acknowledge_pending) {
pri->acknowledge_pending = 0;
q921_rr(pri, 0, 0);
}
}
static void q921_statemachine_check(struct pri *pri)
{
switch (pri->q921_state) {
case Q921_MULTI_FRAME_ESTABLISHED:
q921_send_queued_iframes(pri);
q921_acknowledge_pending_check(pri);
break;
case Q921_TIMER_RECOVERY:
q921_acknowledge_pending_check(pri);
break;
default:
break;
}
}
static pri_event *__q921_receive_qualified(struct pri *pri, q921_h *h, int len)
{
pri_event *ev = NULL;
switch(h->h.data[0] & Q921_FRAMETYPE_MASK) {
case 0:
case 2:
ev = q921_iframe_rx(pri, h, len);
break;
case 1:
switch(h->s.ss) {
case 0:
ev = q921_rr_rx(pri, h);
break;
case 1:
ev = q921_rnr_rx(pri, h);
break;
case 2:
/* Just retransmit */
if (pri->debug & PRI_DEBUG_Q921_STATE)
pri_message(pri, "-- Got reject requesting packet %d... Retransmitting.\n", h->s.n_r);
ev = q921_rej_rx(pri, h);
break;
default:
pri_error(pri, "!! XXX Unknown Supervisory frame ss=0x%02x,pf=%02xnr=%02x vs=%02x, va=%02x XXX\n", h->s.ss, h->s.p_f, h->s.n_r,
pri->v_s, pri->v_a);
}
break;
case 3:
if (len < 3) {
pri_error(pri, "!! Received short unnumbered frame\n");
break;
}
switch(h->u.m3) {
case 0:
if (h->u.m2 == 3) {
ev = q921_dm_rx(pri, h);
break;
} else if (!h->u.m2) {
if ((pri->sapi == Q921_SAPI_LAYER2_MANAGEMENT) && (pri->tei == Q921_TEI_GROUP)) {
pri_error(pri, "I should never be called\n");
q921_receive_MDL(pri, (q921_u *)h, len);
} else {
int res;
res = q931_receive(pri, pri->tei, (q931_h *) h->u.data, len - 3);
if (res == -1) {
ev = NULL;
}
if (res & Q931_RES_HAVEEVENT)
ev = &pri->ev;
}
}
break;
case 2:
ev = q921_disc_rx(pri, h);
break;
case 3:
if (h->u.m2 == 3) {
/* SABME */
if (pri->debug & (PRI_DEBUG_Q921_STATE | PRI_DEBUG_Q921_DUMP)) {
pri_message(pri, "-- Got SABME from %s peer.\n", h->h.c_r ? "network" : "cpe");
}
if (h->h.c_r) {
pri->remotetype = PRI_NETWORK;
if (pri->localtype == PRI_NETWORK) {
/* We can't both be networks */
ev = pri_mkerror(pri, "We think we're the network, but they think they're the network, too.");
break;
}
} else {
pri->remotetype = PRI_CPE;
if (pri->localtype == PRI_CPE) {
/* We can't both be CPE */
ev = pri_mkerror(pri, "We think we're the CPE, but they think they're the CPE too.\n");
break;
}
}
ev = q921_sabme_rx(pri, h);
break;
} else if (h->u.m2 == 0) {
ev = q921_ua_rx(pri, h);
break;
} else
pri_error(pri, "!! Weird frame received (m3=3, m2 = %d)\n", h->u.m2);
break;
case 4:
pri_error(pri, "!! Frame got rejected!\n");
break;
case 5:
pri_error(pri, "!! XID frames not supported\n");
break;
default:
pri_error(pri, "!! Don't know what to do with M3=%d u-frames\n", h->u.m3);
}
break;
}
q921_statemachine_check(pri);
return ev;
}
static pri_event *q921_handle_unmatched_frame(struct pri *pri, q921_h *h, int len)
{
pri = PRI_MASTER(pri);
if (h->h.tei < 64) {
pri_error(pri, "Do not support manual TEI range. Discarding\n");
return NULL;
}
if (h->h.sapi != Q921_SAPI_CALL_CTRL) {
pri_error(pri, "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(pri)) {
if (pri->debug & PRI_DEBUG_Q921_DUMP) {
pri_message(pri,
"Could not find candidate subchannel for received frame with SAPI/TEI of %d/%d.\n",
h->h.sapi, h->h.tei);
pri_message(pri, "Sending TEI release, in order to re-establish TEI state\n");
}
/* Q.921 says we should send the remove message twice, in case of link corruption */
q921_send_tei(pri, Q921_TEI_IDENTITY_REMOVE, 0, h->h.tei, 1);
q921_send_tei(pri, Q921_TEI_IDENTITY_REMOVE, 0, h->h.tei, 1);
}
return NULL;
}
/* This code assumes that the pri structure is the master pri */
static pri_event *__q921_receive(struct pri *pri, q921_h *h, int len)
{
pri_event *ev = NULL;
struct pri *tei;
/* Discard FCS */
len -= 2;
if (pri->debug & (PRI_DEBUG_Q921_DUMP | PRI_DEBUG_Q921_RAW))
q921_dump(pri, h, len, pri->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(pri, (q921_u *)h, len);
}
if ((h->h.tei == Q921_TEI_GROUP) && (h->h.sapi != Q921_SAPI_CALL_CTRL)) {
pri_error(pri, "Do not handle group messages to services other than MDL or CALL CTRL\n");
return NULL;
}
if (BRI_TE_PTMP(pri)) {
if (((pri->subchannel->q921_state >= Q921_TEI_ASSIGNED) && (h->h.tei == pri->subchannel->tei))
|| (h->h.tei == Q921_TEI_GROUP)) {
ev = __q921_receive_qualified(pri->subchannel, h, len);
}
/* Only support reception on our single subchannel */
} else if (BRI_NT_PTMP(pri)) {
tei = pri_find_tei(pri, h->h.sapi, h->h.tei);
if (tei)
ev = __q921_receive_qualified(tei, h, len);
else
ev = q921_handle_unmatched_frame(pri, h, len);
} else if (PTP_MODE(pri) && (h->h.sapi == pri->sapi) && (h->h.tei == pri->tei)) {
ev = __q921_receive_qualified(pri, h, len);
} else {
ev = NULL;
}
if (pri->debug & PRI_DEBUG_Q921_DUMP)
pri_message(pri, "Handling message for SAPI/TEI=%d/%d\n", h->h.sapi, h->h.tei);
return ev;
}
pri_event *q921_receive(struct pri *pri, q921_h *h, int len)
{
pri_event *e;
e = __q921_receive(pri, h, len);
#ifdef LIBPRI_COUNTERS
pri->q921_rxcount++;
#endif
return e;
}
static void q921_establish_data_link(struct pri *pri)
{
q921_clear_exception_conditions(pri);
pri->RC = 0;
stop_t203(pri);
reschedule_t200(pri);
q921_send_sabme(pri);
}
static void nt_ptmp_dchannel_up(void *vpri)
{
struct pri *pri = vpri;
pri->schedev = 1;
pri->ev.gen.e = PRI_EVENT_DCHAN_UP;
}
void q921_start(struct pri *pri)
{
if (PTMP_MODE(pri)) {
if (TE_MODE(pri)) {
q921_setstate(pri, Q921_ASSIGN_AWAITING_TEI);
q921_tei_request(pri);
} else {
q921_setstate(pri, Q921_TEI_UNASSIGNED);
pri_schedule_event(pri, 0, nt_ptmp_dchannel_up, pri);
}
} else {
/* PTP mode, no need for TEI management junk */
q921_establish_data_link(pri);
pri->l3initiated = 1;
q921_setstate(pri, Q921_AWAITING_ESTABLISHMENT);
}
}
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